Free Home & DIY Calculators
Measure rooms, estimate paint and order the right amount of concrete. Simple calculators for home projects, so you buy the right amount the first time.
Most home project mistakes are math mistakes: a second trip to the store because you ran out of paint, a short concrete pour that leaves a weak cold joint, or flooring that is a box short. These calculators turn your measurements into material quantities, with waste allowances built in, so you can plan and price a job before you start.
Start with the square footage calculator to measure any room or yard, even irregular ones, by adding rectangles, circles and triangles. Use the result to price flooring, sod or tile. The paint calculator subtracts doors and windows and tells you how many gallons and quarts to buy for walls, ceiling and primer. The concrete calculator gives cubic yards for a ready-mix order or the number of 40, 60 or 80 lb bags for slabs, footings and post holes.
Popular home & DIY tools
- Square Footage Calculator — area of rooms and yards in any unit, with cost
- Paint Calculator — gallons for walls, ceilings and primer
- Concrete Calculator — yards and bags for slabs, footings and posts
- Mulch, Gravel & Soil Calculator — cubic yards, bags and tons
- Tile Calculator — tiles, boxes and grout
- BTU Calculator — what size air conditioner a room needs
- Roofing Calculator — squares, bundles and underlayment
- Flooring Calculator — boxes, carpet and trim
- Solar Panel Calculator — system size and payback
- Wire Gauge Calculator — right wire size for amps and distance
- Tank Volume Calculator — gallons in a partly full tank
Results are estimates based on standard coverage and yield figures. Check the label on your paint or concrete mix and round up; leftover material is far cheaper than a second delivery.
Home & DIY — all tools
Frequently asked questions
How much extra material should I buy?
Add 10% for most flooring and concrete jobs, and 15% for diagonal tile layouts. For paint, round up to the next quart or gallon and keep the leftovers for touch-ups.
Are these calculators accurate for contractors?
They use standard formulas and typical coverage figures, which is what most estimates are built on. Always check manufacturer specs and local code for structural work.
Do I need to sign up?
No. Every calculator runs in your browser and nothing you enter is stored or sent anywhere.