Calculating your volume is straightforward once you know the Gravel formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Gravel Calculator.
What is Gravel?
The Gravel calculation tells you your volume from a few simple inputs. The figure you are solving for here is the volume.
The Gravel formula
The core formula is:
Volume = Length × Width × (Depth ÷ 12)Here is what each input means:
- Length — a value measured in ft. Example: 20 ft.
- Width — a value measured in ft. Example: 10 ft.
- Depth — a value measured in in. Example: 4 in.
How to calculate it step by step
- Write down the length (for example, 20 ft).
- Write down the width (for example, 10 ft).
- Write down the depth (for example, 4 in).
- Apply the formula above to get your volume.
- Double-check the result with the Gravel Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Length | 20 ft |
| Width | 10 ft |
| Depth | 4 in |
| Volume | 66.67 |
| Cubic yards | 2.47 |
| Approx. weight (tonnes) | 3.02 |
With length of 20 ft, width of 10 ft and depth of 4 in, the volume works out to 66.67.
Example 2
With length of 40 ft, width of 10 ft and depth of 4 in, the volume works out to 133.33.
| Result | Value |
|---|---|
| Volume | 133.33 |
| Cubic yards | 4.94 |
| Approx. weight (tonnes) | 6.04 |
Example 3
With length of 10 ft, width of 10 ft and depth of 4 in, the volume works out to 33.33.
| Result | Value |
|---|---|
| Volume | 33.33 |
| Cubic yards | 1.23 |
| Approx. weight (tonnes) | 1.51 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Gravel Calculator does it instantly, for free, with the formula and a worked example built in.
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