Volume Calculator
Turn length, width and depth into cubic feet, cubic yards, cubic metres and gallons. Depth is entered as a real measurement, so four inches never quietly becomes four feet.
Switching units keeps your measurements. Nothing is reset.
Sections
Watch the units here
Your result appears here
Enter your measurements to see how much material to buy.
How to use this calculator
- 1
Choose rectangular for a slab, trench, box or bed, or round column for a post hole, tube or cylindrical tank.
- 2
Enter length and width in feet, then put the depth in the inches box if that is how you measured it. A four inch slab is 0 ft 4 in, not 4 ft.
- 3
Add a section for each separate part of the job. A slab plus its thickened edge is two sections, added together.
- 4
Read the cubic yards figure if you are ordering ready-mix or bulk aggregate, and the cubic metres figure if your supplier quotes in metric.
A worked example
A 10 ft × 10 ft slab at 4 in thick, plus a 10 ft × 1 ft thickened edge at 12 in deep:
Add the sections together
33.33 ft³ + 10 ft³43.33 ft³
You will need
43.33 ft³
This example is produced by running the calculator above, so it always matches what the tool does.
The formula
A rectangular section is length × width × depth. A cylinder is π times the radius squared times the height, where the radius is half the diameter. Everything is converted to a single internal unit before being added, so mixing feet, inches and metres between sections is safe. One cubic yard is exactly 27 cubic feet.
Getting depth right
Depth is where volume goes wrong
Almost every bad volume estimate is a depth entered in the wrong unit. A 10 ft × 10 ft slab is 1.23 cubic yards at four inches and 14.8 cubic yards at four feet. The inches box exists so that mistake is hard to make.
Order in cubic yards, measure in feet
Ready-mix concrete and bulk aggregate are sold by the cubic yard in the US and by the cubic metre elsewhere. Both are shown, so you can measure in whatever is convenient and order in whatever the supplier uses.
Excavation is not the same as fill
Soil and aggregate bulk up when dug and settle when compacted. This calculator gives the geometric volume of the space; how much loose material that takes depends on the material and how hard it is compacted.
Common questions
- How many cubic feet are in a cubic yard?
- Exactly 27. A cubic yard is three feet in each direction, so divide cubic feet by 27 to get cubic yards.
- How do I enter a four inch slab?
- Leave the feet box empty and put 4 in the inches box. Entering 4 in the feet box would give you twelve times too much concrete.
- Does this include any extra for waste?
- No. This is the geometric volume of the space. The concrete, gravel, mulch and soil calculators add an adjustable overage on top, because the right allowance depends on the material and the job.