Slabwise: Concrete Calculator

Clearstack Labs

About this app

Slabwise works out how many premix bags to buy, how much ready-mix to ask for, how many tons of gravel and how many sticks of rebar a job needs. Enter the size, get the order.

Three calculators in one pocket
Built for driveways, patios, footings and fence posts. Every answer comes with the waste allowance already added, so you buy once.

• Concrete: Slabs, footings, round columns, walls and steps, with an optional landing. See how many 40, 60 or 80 lb bags (or 10–40 kg) to buy, or how much ready-mix to order from the plant.
• Gravel & landscaping: Gravel, crushed stone, sand, mulch and topsoil, for rectangles or circles. Get the volume, an estimated weight in tons, the number of bags and the area covered.
• Rebar grids: Pick the bar size and stick length, set the spacing and edge cover, and Slabwise counts the bars each way, the sticks to buy with lap allowance, and the total weight.

• Feet & inches, with fractions, or metres and centimetres. Switch any time; nothing is lost.
• A live drawing of the shape you're measuring. Tap a dimension on it to change it.
• Cost estimate from your own price per bag, stick or cubic yard.
• History of saved jobs, ready to reopen at the store or the plant.
• No account, no ads, no tracking. Everything stays on your phone.

Available in 16 languages: Deutsch, English, Español, Français, Italiano, Lietuvių, Polski, Português, Română, Русский, Українська, اردو, العربية, हिन्दी, বাংলা, 简体中文.

Your measurements stay yours
Slabwise has no accounts, no analytics and no ads, and it doesn't connect to the internet. Your jobs, prices and settings are stored only on your phone.

Free · Works offline · No account needed

Questions or ideas? [e-mail]