Gravel & Road Base Calculator: measuring notes and method
Use the intended layer thickness
Measure base thickness independently of paver, bedding or asphalt thickness. Varying depths should be separate sections rather than one arbitrary average.
Confirm density and compaction basis
Record any loose-to-compacted conversion explicitly. A waste percentage describes an allowance; it does not establish that conversion.
Formula
Volume = length × width × depth × (1 + waste ÷ 100). Mass = volume × density.
Worked examples in metric and imperial units
Illustrative values match Reset example and stay fixed when you edit the calculator. Both columns describe the same calculation; converted inputs are rounded.
Metric worked example
- Length
- 6 m
- Width
- 4 m
- Finished depth
- 100 mm
- Bulk density
- 1,700 kg/m³
- Waste allowance
- 10 %
Material weight: 4,488 kg
Imperial worked example
- Length
- 19.685 ft
- Width
- 13.1234 ft
- Finished depth
- 3.937 in
- Bulk density
- 106.1275 lb/ft³
- Waste allowance
- 10 %
Material weight: 9,894.3463 lb
Follow the calculation
Lengths in this working are in metres.
- Net volume = 6 × 4 × 0.1 = 2.4 m³.
- Allowance multiplier = 1 + 10 ÷ 100 = 1.1.
- Mass = 2.64 m³ × 1,700 kg/m³ = 4,488 kg.
Gravel calculator in tonnes
A 6 m × 4 m area at 50 mm depth has volume 1.2 m³. At an assumed density of 1,600 kg/m³ with 10% allowance, estimated mass is 2,112 kg, or 2.112 metric tonnes. Replace the example density with your supplier’s value.
Unit conversions
1 m³ = 1,000 L ≈ 1.30795 yd³. One cubic yard is 27 ft³.
For metric tonnes, divide kg by 1,000. For US short tons, divide lb by 2,000; a long ton is 2,240 lb. Confirm your supplier’s unit.
Reviewed 19 October 2026. How calculations are checked · Report a correction