Inputs used
- Length (m)
- Width (m)
- Depth (cm)
- Aggregate density (t/m³)
- Bag size (kg)
gravel calculator
How the Gravel Calculator works
Assumptions, formula, inputs, and practical limits for the Gravel Calculator.
How this estimate works
The calculator turns area and depth into cubic metres, converts volume to weight using aggregate density, adds a small allowance, and rounds bag count up.
- Volume = length x width x depth.
- Weight = volume x aggregate density x a 10% waste and settling allowance.
- Bag count = estimated kg divided by bag size, rounded up.
Outputs generated
- cubic metres
- tonnes
- 20kg bag count
- bulk bag estimate
Worked example
A 5 x 2 m area at 5 cm depth is 0.5 cubic metres. At 1.6 t/m3 with allowance, that is about 0.88 tonnes, or 44 bags if bags are 20 kg.
Limits of the estimate
This is an estimate. Site conditions, compaction, and aggregate type can change the final quantity.
Check depth for the intended use, measure irregular areas carefully, and compare small bags with bulk-bag or loose-load delivery.