Cubic Yards Explained
By the TapeMeasureCalc team · Updated · 6 min read
In the US, almost anything loose and heavy is sold by the cubic yard: topsoil, mulch, gravel, fill dirt and ready-mix concrete. People measure in feet and inches, though, and the conversion is where most bad orders start. Here’s what a cubic yard actually is, how to get there from your measurements, and how far one goes.
What a cubic yard is
A cubic yard is a cube 3 feet on every side. Because 3 × 3 × 3 = 27, it holds 27 cubic feet. In metric it’s 0.7646 cubic metres, a little over three-quarters of a cubic metre.
Don’t confuse it with a square yard, which is a flat area of 9 square feet. Carpet is sold by the square yard; soil and stone are sold by the cubic yard.
From your measurements to cubic yards
Cubic yards = Length (ft) × Width (ft) × Depth (ft) ÷ 27
Depth is the step people trip over, because it’s usually measured in inches. Divide inches by 12 first: 3 in is 0.25 ft, 4 in is 0.333 ft, 6 in is 0.5 ft.
Example: topsoil for a 30 × 20 ft area, 3 inches deep. 30 × 20 × 0.25 = 150 ft³. Divide by 27 and you get 5.56 cubic yards. Most yards sell in half or whole yards, so you’d order 6.
From metric: multiply cubic metres by 1.308 to get cubic yards. A 6 × 4 m area at 100 mm deep is 2.4 m³, which is 3.14 yd³.
How far does a cubic yard go?
Spread at different depths, one cubic yard covers:
| Depth | Coverage |
|---|---|
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
The pattern is easy to remember: 324 divided by the depth in inches. It’s a handy sense check on any order. If your mulch order says 2 yards for a 600 sq ft bed at 3 inches, something’s off, because 600 ÷ 108 is about 5.6.
Yards versus tons
Stone and sand are often priced by the ton, but a cubic yard of gravel and a cubic yard of mulch weigh very different amounts. To convert, you need the material’s density, ideally from the supplier who’s selling it. Dry gravel often lands somewhere around 1.3 to 1.5 US tons per cubic yard, but moisture and stone type move it around. The gravel calculator does the conversion with a density you can change.
Mistakes that lead to bad orders
- Multiplying feet by inches. 20 × 10 × 4 is 800, not 66.7. Convert the depth to feet first.
- Ordering the exact volume. Loose material settles and compacts. Mulch and soil drop after watering; crushed stone shrinks when it’s compacted.
- Forgetting the odd shapes. Measure curved beds and L-shaped areas in pieces and add them up.
- Mixing up square and cubic. A quote “per yard” for soil means per cubic yard.
Do it with the calculators
The cubic yard calculator takes dimensions in any unit, or an area and a depth, and has a converter for any volume. For smaller volumes and litres, use the cubic feet calculator. If it’s mulch, the mulch calculator adds several beds together and counts bags.