Free DIY & Home Improvement Calculators
162 free calculators for concrete, paint, flooring, decking, landscaping and more. Type in your project's dimensions and get a shopping-list result right away, with the formula, a worked example and the sources behind it. Everything runs in your browser, so what you enter never leaves your device.
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All 162 calculators →Most popular
Concrete Slab Calculator
Concrete 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.
Paint Calculator
Use 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 Calculator
Drywall 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.
Flooring Calculator
Flooring calculator for hardwood, laminate, and vinyl plank. Enter room size, box coverage, and layout to get the boxes to buy, with waste included.
Mulch Calculator
Get 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.
Tile Calculator and Cost Estimator
Tile calculator for the tile, thinset, and grout a floor needs. Grout coverage comes from CUSTOM Building Products' table by tile size and joint width.
Formula and worked example
Every calculator explains how the number is produced and walks through one example with real numbers you can check by hand.
Cited sources
Waste factors, coverage rates and material yields come from building codes, industry standards (ASTM, NRMCA, TCNA) and manufacturer spec sheets, cited on the page.
Private by design
Calculations run in your browser. What you type is never sent to a server or stored.
Frequently Asked Questions
Is rightquantity.com really free?
Yes. Every calculator is free to use, with no account, subscription, or paywall.
Do you store the numbers I enter?
No. Every calculator runs in your browser, so nothing you type is sent to a server or saved anywhere.
Read the full Privacy Policy →How accurate are the results?
As accurate as the assumptions each calculator states, but every calculator uses simplified formulas and isn't a substitute for a site visit, a contractor's measurement, or your local building code.
See what each calculator does and doesn't account for →Where do the waste percentages and coverage rates come from?
From building codes, industry standards such as ASTM and the TCNA Handbook, trade-association technical bulletins, and manufacturer spec sheets - never from other calculator sites or unsourced blog posts.
Read our full sourcing policy →How do I know a calculator's formula is right?
Every calculator has a "How to Calculate" section showing the exact formula, a worked example you can verify by hand, and links to the source for any figure it uses.
See our research and methodology →What if you don't have the calculator I need?
Tell us. We add calculators based on what people actually ask for.
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