Concrete Slab Calculator
Cubic yards and bags for a patio, shed base, driveway or floor slab.
Works in your browser. Nothing you type is sent to us.
What you are pouring
Solid steps poured against a wall. The top platform is any landing deeper than a tread.
Uneven ground, spillage and over-dig all eat concrete. 10% is usual; use more on rough ground.
Bags of mix
| Bag | Yield | Bags | Cost |
|---|
Bag yields are the typical figures printed on premixed concrete bags; check yours. Worked out in your browser, nothing you type is sent to us.
Concrete Slab Calculator at a glance
- Price
- Free
- Data sent to us
- None, it runs in your browser
- Sign-up
- Not needed
- Shapes
- Slab, footing, column, wall, steps
- Gives
- Cubic yards, cubic metres, bags, weight, cost
- Units
- ft and in, or m and cm
How to use Concrete Slab Calculator
- Choose the shapeSlab for a patio or floor, Footing for a strip under a wall, Column for a round pier or post hole, Wall for a formed wall, or Steps for solid stairs.
- Type the measurementsPick feet and inches or metres and centimetres, type the dimensions and how many pieces, and set the waste allowance. Fractions like 3 1/2 work.
- Read the volume and bagsThe cubic yards or metres with waste, the ready-mix amount to order, and the bag count for every size update as you type. Add a price per yard or per bag to see the cost.
Type the slab's length and width in feet or metres and its thickness in inches or centimetres, and read the volume with 10% added for waste, the ready-mix quantity rounded to the quarter yard and the number of bags of each size. A 4 inch slab is usual for patios, paths and shed bases; driveways and garage floors are typically 5 to 6 inches, and the thickness you type is the single biggest factor in the answer.
How it works
Concrete Slab Calculator is a web page that does its work on your own device. Everything you type or choose is worked out by your browser and never sent to a server, so nothing is stored and there is nothing to delete. There is no account, no sign-up and no limit on how often you use it.
Slab thickness
Patios, paths and shed bases are commonly 4 inches (10 cm). Driveways and garage floors carrying vehicles are usually 5 to 6 inches, and anything carrying heavy equipment is engineered. Thickness is set by the load and by your local code, not by the calculator.
Questions
How much concrete for a 10 by 10 slab?
At 4 inches thick, 1.23 cubic yards before waste and about 1.36 yards with 10% added: 62 bags of 80 lb, or a short ready-mix load of 1.5 yards.
Other shortcuts
Concrete Calculator · Concrete Footing Calculator
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