RightFiguresOne rectangular slab
Volume is length times width times thickness. Length and width are in international feet. Thickness is in inches. One international yard is exactly 3 international feet, so one cubic yard is 27 cubic feet. The waste percent you type scales that volume before the result is rounded.
This is not the paint calculator or the flooring calculator. Those pages count gallons and boxes. This page has no price, so it is not a unit-price comparison.
NIST Appendix B defines the international yard as 0.9144 meters and the international foot as 0.3048 meters. This page uses that foot. It does not use the U.S. survey foot. Firestone’s concrete specification says a ready-mixed batch ticket includes the cubic yards and the mix. This page does not produce that ticket.
10 feet by 10 feet by 4 inches
10.00 feet by 10.00 feet by 4.00 inches, with 0% waste, is 33.33 cubic feet and 1.23 cubic yards. The exact feet are 100/3 and the exact yards are 100/81. Each figure is rounded half up on its own. The displayed feet are not converted again to make the yards.
The same slab with 10% waste is 36.67 cubic feet and 1.36 cubic yards. Enter 0 when you are not adding waste. A blank field is not zero, and this page does not assume 10%.
Half up, including 1.005
10.00 feet by 12.06 feet by 0.10 inches is exactly 1.005 cubic feet. The displayed volume is 1.01 cubic feet and 0.04 cubic yards. A rule that leaves an even digit unchanged would keep 1.00. This page does not use that rule.
A supplier may sell a quarter yard, a half yard, or a full truck. Those increments are the supplier’s. This page shows the calculated volume after the waste percent you entered.
What this leaves out
A circular pier, a stepped footing, and a second rectangle are not included. The page does not choose a thickness, a strength, a water-cement ratio, reinforcement, or a count of bags. The largest accepted slab, 1,000.00 feet by 1,000.00 feet by 48.00 inches at 100% waste, is 296,296.30 cubic yards and is still shown.
Frequently asked questions
Does this page choose how thick the slab should be?
No. Thickness is the number you enter. The result is the volume of that
rectangle. It is not a structural specification.
Will a supplier deliver this exact volume?
Not necessarily. A batch ticket states the cubic yards the plant batches. This
page does not round up to the plant’s selling increment.
Are the dimensions sent to analytics?
No. Analytics may record that this calculator ran. Length, width, thickness,
waste, and the volumes stay in this browser.
Sources & review
- Guide to the SI, Appendix B — National Institute of Standards and Technology
- Section 400 — Concrete Work — Town of Firestone
Last reviewed: . The formula is reproduced above so you can check the math independently.
Educational estimate only. This page does not set a thickness, a mix, or the amount a supplier will sell.