Free DIY Calculators and Charts

These tools do the arithmetic and the look-ups for common DIY jobs so you buy the right amount the first time. Each one shows its formula, a worked example and the sources behind its numbers, and runs entirely in your browser.

Pouring a slab, setting fence posts or building a footing? The concrete calculator gives cubic yards and the number of 40, 60 and 80 lb bags, using the yields printed by Quikrete and Sakrete. For the gravel base, mulch or topsoil, use the gravel, mulch and topsoil calculator, which adds tons for gravel from a state DOT weight table.

Painting a room? The paint calculator turns room size, doors, windows and coats into gallons using manufacturer coverage figures. Building something out of wood? The screw size and pilot hole chart shows the screw diameter, pilot hole and clearance hole for each gauge, in inches and millimetres.

We publish no prices of our own. Where a calculator needs a cost or a size, you type in your own measurements or local quote.