Free project calculators
Home and Garden Project Calculators
Free, simple calculators for real outdoor and home projects. Enter your measurements and get quantities to buy, with the math shown and sources linked.
Part of our outdoor-career toolkit
Thinking about swapping an office job for outdoor work? These are the same sums landscapers and gardeners do every day. Read From office to outdoors for the career side.
Choose a calculator
Pick the one that matches your project. The label on each card shows the project type.
- LandscapingMulch CalculatorCubic yards and bags for beds and tree rings, with a top-up option.
- LandscapingGravel CalculatorPaths, drives and gravel beds: cubic yards, tons and bags, one layer at a time.
- ConcreteConcrete CalculatorSlabs, patios and round footings: cubic yards and 40, 60 or 80 lb bags.
- DeckingDeck Board CalculatorHow many deck boards to buy, with gaps and the last-board cut.
- RoofingRoof Pitch CalculatorPitch, angle, slope factor and roof area from a rise and run.
- MeasuringSquare Footage CalculatorRooms, patios and yards: add and subtract simple shapes.
How we build and check these calculators
- Every calculator shows its formula in plain words, under “How we calculate”.
- Figures come from primary sources: manufacturers (such as how much a bag of concrete makes), university extension services, government agencies and industry standards bodies. We link every source.
- Each calculator is tested against worked examples calculated by hand, including metric units and unusual inputs, before it is published.
- We use AI tools to help write code and text, and everything is reviewed before it goes live.
- The math runs in your browser. The measurements you type are not sent to us.
More project calculators are being added. Results are estimates: check local codes and product labels, and buy a little extra.