All 162 Calculators
Every calculator is free, runs in your browser, and shows its formula, a worked example and the sources behind the numbers. Search by name, or browse a category.
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Concrete & Masonry
Slabs, footings, block and mortar - by the bag or by the truck
- Concrete Slab CalculatorConcrete slab calculator for patios, sidewalks and pads: get cubic yards, a ready-mix order size and 40, 60 or 80 lb bag counts, with waste included.
- Concrete Footing CalculatorFind the cubic yards, ready-mix order size and 40, 60 or 80 lb bag count for a strip footing trench, with 8% waste and an optional price included.
- Concrete Block CalculatorWork out the 8x8x16 concrete blocks and 80 lb mortar bags for a CMU wall, with door and window openings subtracted, breakage included, and optional costs.
- Concrete Block Fill CalculatorEstimate core-fill grout for CMU block walls, from reinforced-cell partial grouting to solid grouting, in coarse or fine grout, with waste included.
- Concrete Mix CalculatorBatch concrete from raw materials: get the portland cement bags, sand and gravel for a target volume at the 1:2:3 mix, with 5% waste included.
- Concrete Reinforcing Mesh CalculatorWork out the 5x10 ft sheets or 5x150 ft rolls of 6x6 welded wire mesh for a slab, with splice overlap and trim waste included, plus an optional cost.
- Concrete Steps CalculatorGet the concrete volume, ready-mix order size and bag count for a solid poured staircase, from the number of steps, rise, run and width you enter.
- Concrete Weight CalculatorFind how much a poured slab or footing weighs in pounds and tons, from its length, width, thickness and an adjustable concrete density input.
- Rebar Weight and Size CalculatorLook up the nominal diameter and weight per foot for US rebar sizes #3 through #18, and get the total weight for any length you enter, in lb and tons.
- Rebar Material CalculatorGet the rebar sticks, total length and weight for a two-way grid in a slab or footing, with cover, spacing, waste and bar size all adjustable.
- Block Mortar CalculatorGet the 80 lb mortar mix bags you need for a set number of 8x8x16 blocks or standard bricks, with waste and an optional bag price included in the result.
- Concrete Sealer CalculatorEstimate concrete sealer for a patio, driveway or garage floor by area, sealer type and number of coats, with gallons rounded up for easy ordering.
- Excavation CalculatorEstimate the bank and loose soil volume for a dig in cubic yards, plus the truck loads to haul it away, adjusted for soil type and truck size.
- ICF Block & Concrete CalculatorGet the ICF block count and concrete fill in cubic yards for a wall, from its length, height and a 4, 6 or 8 in. core width, with both results rounded up.
- Epoxy/Resin Coating CalculatorEstimate epoxy or resin gallons for a garage floor, countertop or bar top from area, product coverage and number of coats, rounded up for ordering.
- Crawl Space Vapor Barrier CalculatorWork out how many rolls of crawl space vapor barrier sheeting you need for a floor, with seam overlap included and roll coverage you can adjust.
Wall & Ceiling
Paint, drywall and wallpaper - by the room, not just the wall
- Paint CalculatorUse this paint calculator to find the gallons of paint and primer a room needs, with doors, windows, the ceiling, and coats factored in. Wall area shown too.
- Drywall CalculatorDrywall calculator for sheets, screws, and joint compound, with doors, windows, the ceiling, and waste factored in. Pick 4x8 or 4x12 sheets and 1/2 or 5/8 in.
- Wallpaper CalculatorWallpaper calculator for the double rolls a room needs. Roll width, pattern repeat, and waste are all included, with standard 20.5 in. or wide 27 in. rolls.
- Insulation CalculatorInsulation calculator for batt, blown-in, or rigid foam. Get the packages a wall, ceiling, or attic needs from your product's rating, with waste added.
- Spray Paint Coverage CalculatorSpray paint coverage calculator for furniture, trim, and crafts. Enter the area, the number of coats, and your can's rated coverage to get the cans to buy.
Flooring
Tile, carpet, laminate and hardwood - waste sized to your layout
- Flooring CalculatorFlooring calculator for hardwood, laminate, and vinyl plank. Enter room size, box coverage, and layout to get the boxes to buy, with waste included.
- Tile Calculator and Cost EstimatorTile calculator for the tile, thinset, and grout a floor needs. Grout coverage comes from CUSTOM Building Products' table by tile size and joint width.
- Carpet Calculator and Price EstimatorCarpet calculator for 12 ft and 15 ft rolls. Shows roll-width strips, linear feet of roll, and square yards to buy, plus an optional cost estimate.
- Subfloor CalculatorSubfloor calculator for plywood or OSB sheets, from floor area and a 4x8 or 4x4 sheet size, with waste added and the count rounded up to whole sheets.
- Tile Layout CalculatorTile layout calculator for one room direction. Get edge cut widths and tile count in a row, and see whether the start must shift to avoid a thin sliver.
Lawn & Landscaping
Mulch, soil, gravel, sod and stone - bags or bulk by the yard
- Mulch CalculatorGet the cubic yards and 2 cu ft bags of mulch a bed needs at your chosen depth, with a bagged-versus-bulk recommendation and optional cost estimates.
- Gravel CalculatorEstimate the cubic yards and tons of gravel for a path, driveway topping, or bed, with an adjustable density for the gravel type you are buying.
- Soil CalculatorGet the cubic yards or bags of topsoil or garden soil to fill a raised bed or garden bed, with a settling allowance and a bagged-vs-bulk recommendation.
- Sod CalculatorCalculate how many pallets of sod a lawn needs from its length and width, with a waste allowance and your sod supplier's coverage per pallet.
- Sod Weight CalculatorFind the weight of a sod order in pounds and tons from the lawn's length and width, with an adjustable weight per square foot for hauling checks.
- Stone CalculatorGet the cubic yards and tons of decorative or landscape stone for a bed or border from its size and depth, with an adjustable density for the product.
- River Rock CalculatorGet the cubic yards and tons of river rock for a bed, dry creek, or drainage feature, from its length, width, and depth, with adjustable density.
- Retaining Wall CalculatorEstimate retaining wall blocks, courses, and blocks per course from your wall's length and height, using the face size of your manufacturer's block.
- Grass Seed CalculatorCalculate pounds of grass seed for a lawn from its length, width, and seeding rate, with a waste allowance and an optional seed price estimate.
- Pool Volume CalculatorGet your pool's volume in gallons and cubic feet from its shape, size, and shallow and deep end depths, for rectangular, circular, or oval pools.
- Acreage CalculatorUse this acreage calculator to get a lot's size in acres and square feet from its length and width. Irregular lots can be split into rectangles first.
- Elevation Grade CalculatorUse this elevation grade calculator to find percent grade, slope ratio, and angle from a rise and run, with code checks for drainage and ramps.
- Lawn Mowing CalculatorEstimate how many hours a mowing job takes, and its labor cost, from your lawn area, mower deck width, travel speed, and efficiency for overlap and turns.
- Sand CalculatorEstimate the cubic yards and tons of sand for a sandbox, paver bedding layer, or play area, with an adjustable density for dry, damp, or wet sand.
- Plant and Flower CalculatorWork out how many plants your bed needs at a chosen spacing, for a square grid or a denser staggered layout, with a loss allowance added to the count.
- Lawn Fertilizer CalculatorWork out how many bags of lawn fertilizer your yard needs from its area, target nitrogen rate, and the first N-P-K number printed on the bag.
- Rainwater Harvesting CalculatorEstimate how many gallons of rainwater a roof collects from a given rainfall, with a runoff coefficient for losses, to size a barrel or cistern.
- Flagstone CalculatorEstimate the tons of flagstone for a patio or walkway from its area, thickness, density, and waste allowance, with the total weight in pounds too.
- Landscape Edging CalculatorGet the edging sections and stake count for a rectangular or circular garden bed, from its dimensions and your edging product's section length.
- Sprinkler Zone CalculatorFind how many sprinkler heads one zone can run at your available GPM, and how many zones your irrigation system needs to cover all of its heads.
- Fire Pit CalculatorGet the blocks per course, total block count, and gravel base in cubic yards for a round DIY fire pit, from its interior diameter and block width.
- Raised Garden Bed CalculatorGet the number of boards and corner posts for a raised garden bed frame, plus its true height, from its length, width, board size, and layer count.
- French Drain CalculatorGet the gravel in cubic yards, filter fabric in square feet, and pipe length for a French drain trench from its length, width, depth, and pipe size.
- Ramp Length CalculatorFind the horizontal run and surface length a ramp needs to climb a set rise in inches, at the ADA's 1:12 maximum slope or a gentler 1:16 or 1:20 ratio.
Deck & Patio
Deck boards, pavers and the base layers underneath them
- Paver Calculator and Price EstimatorUse this paver calculator to get pavers, gravel base, bedding sand and polymeric sand for a patio as one shopping list from one set of dimensions.
- Paver Base CalculatorUse this paver base calculator for the tons and cubic yards of compacted base under a patio or walkway, with adjustable depth, density and waste.
- Deck Board Material CalculatorUse this deck board material calculator to find the stock boards to buy, with the row count and total linear feet, including waste, behind the number.
- Deck Joist Span CalculatorDeck joist span calculator from IRC Table R507.6. Check whether 2x6 to 2x12 Southern Pine joists span your deck at 12, 16, or 24 in. on center.
- Deck Beam Span CalculatorDeck beam span calculator from AWC DCA 6 Table 3A. Check if a 2-ply or 3-ply 2x beam in Southern Pine spans between posts for your joist span.
- Deck Footing Size CalculatorDeck footing size calculator from AWC DCA 6 Table 4. Get the round or square footing size, thickness, and max post height for Southern Pine posts.
- Deck Railing CalculatorDeck railing calculator for balusters, posts, and guard height. Counts balusters so the gap stays under the 4 in. code limit, with the 36 in. height rule.
- Baluster CalculatorUse this baluster calculator to count balusters for a railing section and see the even spacing and actual gap that keep every opening under your maximum.
- Deck Stain CalculatorUse this deck stain calculator to estimate gallons of stain or sealer from surface area, coat count and coverage rate, with an optional cost line.
- Polymeric Sand CalculatorUse this polymeric sand calculator to find how many 50 lb bags fill your paver joints, from patio area, paver size, joint width and joint depth.
- Pergola CalculatorUse this pergola calculator to count posts, beam feet, rafters and rafter length for a free-standing pergola from its footprint and spacing choices.
Roofing
Shingles, underlayment and metal roofing, sized for waste by roof complexity
- Roofing Material CalculatorRoofing material calculator for shingle bundles, underlayment, starter strip, ridge cap and drip edge, from footprint, pitch and edge lengths.
- Roof Pitch CalculatorRoof pitch calculator that turns any rise and run measurement into the X in 12 pitch, a ratio, an angle in degrees and the roof area multiplier.
- Ice & Water Shield CalculatorIce and water shield calculator for eave and valley runs. Get the roll count and waste-adjusted area, with a 100 ft eave and 20 ft valley example.
- Metal Roofing CalculatorMetal roofing calculator for panel count, total panel length and fasteners, using effective coverage width and panels cut to the slope length.
- Plywood Sheathing CalculatorPlywood sheathing calculator for roof decking sheets in 4x8, 4x9 or 4x10 sizes, from footprint area, pitch and waste, with a worked example.
- Gutter CalculatorGutter calculator for gutter sections, hangers, end caps and downspouts from your gutter run and roof area, with downspout sizing and a 150 ft worked example.
- Attic Ventilation CalculatorAttic ventilation calculator for the net free vent area your attic needs, split between soffit and ridge vents, with a 1,200 sq ft worked example.
- Roof Truss CalculatorRoof truss calculator for truss count from roof length and 16 or 24 in. spacing, with a 30 ft worked example and a note on what it excludes.
- Hip & Valley Rafter Length CalculatorHip and valley rafter length calculator for any common rafter run and roof pitch, with the diagonal factor and a 12 ft, 6:12 worked example.
Measurement
Square footage, cubic yards and unit conversions used across every project
- Linear Feet to Square Feet CalculatorLinear feet to square feet calculator for flooring, decking, siding, or trim. Enter the length and the board width to see the coverage in sq ft.
- Square Footage CalculatorSquare footage calculator for rectangles, circles, and triangles. Enter the dimensions and see the area in sq ft, using the exact formula for each shape.
- Cubic Yards CalculatorWork out the cubic yards of concrete, mulch, or gravel an area needs from its length, width, and depth in inches. Shows cubic yards and cubic feet.
- Cubic Yards to Tons CalculatorCubic yards to tons calculator for gravel, mulch, soil, sand, and other bulk materials. Set the volume and density to get the weight in tons.
- Cubic Feet CalculatorGet the volume of a box, room, or bin in cubic feet from its length, width, and height. Prefilled defaults show a live result along with the math.
- Tank Volume CalculatorGet a cylindrical tank's full volume in gallons and cubic feet from its diameter and length. Use this tank volume calculator for upright or horizontal tanks.
- Feet and Inches Length CalculatorFeet and inches length calculator for adding or subtracting two measurements. The carrying and borrowing across 12 inches is handled for you.
- Inch Fraction CalculatorInch fraction calculator for turning decimal inches into the nearest 8th, 16th, 32nd, or 64th, with the exact decimal shown so you can see the rounding.
- Scale Conversion CalculatorScale conversion calculator for model railroads, dollhouses, and architectural drawings. Enter a measurement and a ratio like 1:48 to convert it either way.
- Square Yards CalculatorSquare yards calculator for carpet and flooring pricing. Enter a room's length and width to see its area in both square yards and square feet.
- Square Meters CalculatorSquare meters calculator for metric area figures from feet. Enter length and width in feet to get your space in square meters and square feet.
- Square Inches CalculatorGet a small rectangle's area in square inches and square feet from its length and width in inches. Useful for tile samples, small panels, and trim pieces.
- Cubic Inches CalculatorCubic inches calculator for small boxes, containers, and pieces of material. Enter the length, width, and height in inches for both volume units.
- Cubic Meters CalculatorCubic meters calculator that converts a length, width, and height in feet into a metric volume. Get the result in cubic meters and cubic feet at once.
- Square Feet to Cubic Feet CalculatorTurn a known floor area into cubic feet by entering its depth in inches. You get a live result plus the conversion steps, shown in a worked example.
- Square Feet to Cubic Yards CalculatorConvert a known area and depth into cubic yards for ordering mulch, gravel, or concrete. Live result in cubic yards and cubic feet, plus a worked example.
- Cylinder Cubic Footage CalculatorCylinder cubic footage calculator for planters, bins, silos, and round footing forms. Enter the diameter and height to get the volume in cubic feet.
- Cylinder Cubic Yardage CalculatorCylinder cubic yardage calculator for sonotube footings and piers. Enter the form diameter, depth, and count to get the concrete needed in cubic yards.
- Perimeter CalculatorPerimeter calculator for fencing, edging, and trim. Enter a rectangle, circle, or triangle's dimensions to get the total distance around it in feet.
- Firewood CalculatorFirewood calculator that turns a stack's dimensions and split length into cords and cubic feet, so you can compare a pile against a full cord.
- Ladder Angle CalculatorLadder angle calculator for extension ladders. Enter the working height to get the base distance, placement angle, and recommended ladder length.
Fence
Posts, rails, pickets and gates for a full fence run
- Fence CalculatorUse this fence calculator to count posts, rails and pickets for a wood fence run. Enter length and post spacing to get one estimate, including actual spacing.
- Post Hole Concrete CalculatorUse this post hole concrete calculator to count bags for fence or deck posts. Set hole diameter, depth, post size and bag size to subtract the post's volume.
- Vinyl Fence CalculatorUse this vinyl fence calculator to count 6 ft or 8 ft panels and posts for a run, plus the length the fence will actually cover once panels are whole.
- Fence Stain CalculatorUse this fence stain calculator for gallons of stain or sealer, based on sides stained and number of coats. Add a price per gallon to see the estimated cost.
- Chain Link Fence CalculatorUse this chain link fence calculator for fabric rolls, top rail, line and terminal posts, and tension wire. Enter length, post spacing, and gate count.
- Fence Post Depth CalculatorUse this fence post depth calculator to find hole depth from post height, a 24 in. minimum and frost depth. Total post length to buy is included.
Driveway
Asphalt, concrete and gravel driveways, by depth and compaction
- Gravel Driveway CalculatorThis gravel driveway calculator sizes each layer separately, with a compaction allowance for loose material, so you order enough base and topping.
- Asphalt CalculatorUse this asphalt calculator to find the tons of hot-mix asphalt for your driveway or path, from its length, width and compacted thickness, with an example.
- Concrete Driveway CalculatorUse this concrete driveway calculator to size a ready-mix pour and plan control joints, with a 50 ft example and an optional price per cubic yard.
- Asphalt Sealer CalculatorUse this asphalt sealer calculator to work out how many gallons of sealcoat your driveway needs, based on its size, coat count and coverage rate.
- Ice Melt / Deicing Salt CalculatorUse this ice melt calculator to get the bags and total pounds of deicing salt for a driveway, walkway or parking area, from its size and rate.
Siding
Vinyl, brick, board-and-batten and lap siding by wall area
- Siding Material CalculatorSiding material calculator for wall area and the siding squares to order, with doors and windows subtracted. Works for any siding sold by the square.
- Vinyl Siding CalculatorVinyl siding calculator for panel boxes, starter strip, corner posts, and J-channel. Enter house size, wall height, doors, windows, and outside corners.
- Brick CalculatorBrick calculator for brick count, 80 lb mortar bags, and wall area. Enter the wall size, brick face dimensions, and joint width to get your numbers.
- Board and Batten Siding CalculatorBoard and batten siding calculator for boards, battens, and total linear feet of a wall. Set wall length, wall height, board width, and gap between boards.
- Clapboard and Lap Board Siding CalculatorClapboard siding calculator for courses, stock boards, and total linear feet on a lap siding wall. Set wall size, board width, overlap, and stock length.
- Stone Veneer CalculatorStone veneer calculator for flat and corner boxes, from wall area and outside corner length. Adjust box coverage to match your product's rating.
- House Wrap / Weather Barrier CalculatorHouse wrap calculator for rolls of weather barrier, with seam overlap included. Enter your total exterior wall area and the coverage of one roll.
Carpentry & Trim
Framing, trim, board footage and plywood layouts
- Framing Stud CalculatorFraming stud calculator for 16 or 24 in. on-center walls: get the stud count and plate lumber length, with an allowance for corners and blocking.
- Trim and Molding CalculatorTrim and molding calculator for baseboard or crown molding: get the stock pieces to buy and net length from room size, doors and waste for your project.
- Board Foot CalculatorBoard foot calculator for hardwood and specialty lumber: get board feet per board, the total for your order and an estimated cost from its dimensions.
- Plywood CalculatorPlywood calculator for subfloors, shelving and workbenches: get the sheet count for 4x8 or 4x4 sheets with waste and an optional cost estimate.
- Lumber Weight CalculatorLumber weight calculator for dimensional lumber: get the weight per piece and total weight from nominal size, length, quantity and wood density.
- Rafter Length CalculatorRafter length calculator for a common rafter: enter run, overhang and roof pitch to get the rafter length and total rise in feet for your roof framing.
- Cabinet Door CalculatorCabinet door calculator for full overlay or inset styles: get the finished door width, height and total area from your cabinet opening size.
- Wainscoting Layout CalculatorWainscoting layout calculator for evenly spaced panels: get the panel count, actual panel width, stile count and wall area from your wall width.
- Board and Batten Layout CalculatorBoard and batten layout calculator for an interior accent wall: get the batten count, actual gap width, total batten length and cap rail length.
- Check Square Calculator (3-4-5 Method)Check square calculator using the 3-4-5 method: get the expected diagonal for any two leg lengths and see how far a measured corner is out of square.
- Stair Stringer CalculatorStair stringer calculator for risers, treads and stringer board length, checked against the 7.75 in. max riser and 10 in. min tread limits for your stairs.
- Shed Material CalculatorShed material calculator for a small DIY shed shell: get wall studs, wall and roof sheathing sheets and roofing squares from footprint and roof pitch.
- Kitchen Cabinet Linear Feet CalculatorKitchen cabinet linear feet calculator for a rough base and wall cabinet count, plus total linear feet to compare cabinet quotes side by side.
- Countertop Slab CalculatorCountertop slab calculator for stone or quartz: get the slab count and waste-adjusted area from your countertop size and the usable area of one slab.
- Metal Weight CalculatorMetal weight calculator for steel, aluminum and stainless bar, plate and tube: enter shape, dimensions and length to get the total weight and weight per foot.
- Miter Angle CalculatorMiter angle calculator for baseboard, casing and chair rail: get the saw angle for each piece from any corner, including out-of-square walls.
- Egress Window Size CalculatorEgress window size calculator for bedroom and basement openings: check net clear area, width, height and sill height against the IRC R310 limits.
- Guardrail & Handrail Height CalculatorGuardrail and handrail height calculator: check a deck guardrail against the 36 in. IRC minimum or a stair handrail against its 34 to 38 in. range.
- Crown Molding Angle CalculatorCrown molding angle calculator for compound miter and bevel saw settings. Enter your corner angle and molding spring angle to get both cut angles for your saw.
Plumbing & HVAC
Pipe volume, airflow and equipment sizing basics
- Pipe Volume CalculatorUse this pipe volume calculator to find how many gallons or cubic feet of water a pipe run holds, from its inner diameter, with a 100 ft example.
- Furnace BTU CalculatorUse this furnace BTU calculator to estimate heating capacity from square footage, climate, and insulation, with a 2,000 sq ft example and a Manual J note.
- CFM Calculator (Air Changes per Hour)Use this CFM calculator to find the fan airflow a room needs for a target air changes per hour, or the ACH a known fan delivers in that room.
- Flow Rate CalculatorUse this flow rate calculator to get a pipe's GPM from its inner diameter and water velocity, with the exact gallons-per-cubic-foot factor and a 2 in. example.
- Window AC Size CalculatorUse this window AC size calculator to match a room's area, sun exposure, occupants, and kitchen use to ENERGY STAR's BTU sizing guidance, with a worked example.
- Water Velocity CalculatorUse this water velocity calculator to find how fast water moves in a pipe from its flow rate and inner diameter, with a 49 GPM, 2 in. example.
- Refrigerant Line Charge CalculatorUse this refrigerant line charge calculator to find the ounces to add for a line set longer than the factory pre-charge, using your unit's own figures.
- Pipe Offset CalculatorUse this pipe offset calculator to get the travel and run for a 22.5°, 30°, 45°, or 60° offset, with a worked 12 in. example and a note on fitting takeout.
- Pipe Size CalculatorUse this pipe size calculator to find the inner diameter for a target GPM at a chosen velocity, with a 49 GPM example and round-up guidance for stock pipe.
- Tons to BTU CalculatorUse this tons to BTU calculator to convert a central AC or heat pump's cooling capacity from tons to BTU per hour, with a 3 ton example and the exact factor.
- BTU to Watts CalculatorUse this BTU to watts calculator to convert a furnace, air conditioner, or space heater rating into watts, with a 12,000 BTU/hr example and the factor.
- BTU to kW CalculatorUse this BTU to kW calculator to turn any furnace or air conditioner rating into kilowatts with the exact 0.00029307107 factor. Worked example included.
- BTU to HP CalculatorUse this BTU to HP calculator to convert any BTU per hour rating into mechanical horsepower, with a 12,000 BTU/hr worked example and the exact factor.
- Water Heater Size CalculatorUse this water heater size calculator to estimate a storage tank size from household size and usage, with a 3-person example and a First Hour Rating note.
- Tankless Water Heater Sizing CalculatorUse this tankless water heater sizing calculator to find the BTU/hr a unit needs from your flow rate, incoming water temperature, and target output.
- Glycol CalculatorUse this glycol calculator to work out concentrate and water volumes for hydronic freeze protection, with a 50 gallon, 30% example you can adjust.
- Pipe Thermal Expansion CalculatorUse this pipe thermal expansion calculator to see how far copper, steel, PVC, CPVC, or PEX grows over a run, from its length and temperature change.
- Sump Pump Sizing CalculatorUse this sump pump sizing calculator to estimate pump cycles per hour from basin size, drawdown, pump capacity, and inflow rate, with a worked example.
- Pipe Weight CalculatorUse this pipe weight calculator to get the weight per foot and total weight of steel or stainless pipe by nominal size, schedule, and length.
- Dehumidifier Sizing CalculatorUse this dehumidifier sizing calculator to find the pints-per-day capacity a room needs from its square footage and dampness, rounded to a standard unit.
- Baseboard Heater Length CalculatorUse this baseboard heater length calculator to find the feet of heater a room needs, its wattage, and the circuit amps it draws from a BTU/hr load.
- Water Pressure to Head Height CalculatorUse this water pressure to head height calculator to convert PSI to feet of head, or back, for well and irrigation planning, with a 50 PSI example.
- Rolling Offset CalculatorUse this rolling offset calculator to get the travel and run for a compound pipe offset from its vertical and horizontal legs, with a worked 45° example.
- Water Softener Sizing CalculatorUse this water softener sizing calculator to find the grain capacity your household needs from occupant count and water hardness, with a worked example.
Electrical
Ohm's Law, voltage drop, conduit fill and other basic DIY electrical math
- Ohm's Law CalculatorUse this Ohm's Law calculator to get resistance in ohms and power in watts from any voltage and current reading. Includes the formulas and a worked example.
- Voltage Drop CalculatorUse this voltage drop calculator to find the drop on a wire run in volts and percent, plus the smallest wire gauge that stays within the 3% guideline.
- Parallel Resistance CalculatorParallel resistance calculator for up to four resistors. Enter each value in ohms to get the combined total, plus the formula and how it differs from series.
- Watts, Amps & kVA CalculatorUse this watts to amps calculator to convert watts, kVA and amps for single-phase or three-phase circuits. Adjust power factor for motors and electronics.
- Conduit Fill CalculatorUse this conduit fill calculator to check wire fill against NEC Chapter 9 limits. Get the fill percentage and the most wires of one size the conduit allows.
- EV Charger Circuit CalculatorUse this EV charger circuit calculator to find the minimum breaker and wire gauge for a Level 2 charger, sized to the NEC 125% rule for copper or aluminum.
- Ceiling Fan Size CalculatorUse this ceiling fan size calculator to get a recommended blade diameter from your room's square footage, with notes on downrods and large rooms.
- Smoke & CO Detector Placement CalculatorUse this smoke and CO detector placement calculator to estimate minimum alarm counts from bedrooms, stories and fuel-burning appliances, per IRC rules.
- Electrical Box Fill CalculatorUse this box fill calculator to check NEC volume for your wires. Get the required cu in., the most conductors your box fits, and a pass or fail check.
- Recessed Lighting Layout CalculatorUse this recessed lighting layout calculator to get a fixture count and grid spacing from room length, width and ceiling height. Ambient light only.