How this calculator works
A gravel drive is two layers: a compacted sub-base of MOT Type 1 and a top layer of 20 mm gravel. Each is the area times its depth in metres, plus an allowance, times the weight per cubic metre of the stone (2.2 tonnes for compacted MOT Type 1 and 1.6 for gravel).
Worked example: a 6 × 5 m drive (30 m²) with a 150 mm sub-base and 50 mm of gravel needs 10.9 tonnes of MOT Type 1 and 2.5 tonnes of 20 mm gravel: 13.4 tonnes in all, with 33 m² of membrane and 22 m of edging.
Stone by drive size (150 mm MOT Type 1, 50 mm gravel)
With allowances of 10% on the sub-base and 5% on the gravel.
| Drive | Area | MOT Type 1 | 20 mm gravel | Total |
|---|---|---|---|---|
| 3 × 5 m | 15 m² | 5.4 tonnes | 1.3 tonnes | 6.7 tonnes |
| 3 × 10 m | 30 m² | 10.9 tonnes | 2.5 tonnes | 13.4 tonnes |
| 5 × 5 m | 25 m² | 9.1 tonnes | 2.1 tonnes | 11.2 tonnes |
| 6 × 5 m | 30 m² | 10.9 tonnes | 2.5 tonnes | 13.4 tonnes |
| 6 × 8 m | 48 m² | 17.4 tonnes | 4.0 tonnes | 21.5 tonnes |
Tips before you buy
- Compact the sub-base in layers of about 100 mm with a plate compactor, then lay the membrane and the grid before the gravel.
- Use an edging to hold the gravel in, especially next to a lawn or the pavement.
- Choose the delivery with care: a bulk bag or a loose load is dropped where the lorry can stop.
- A very thick layer of gravel is hard to walk and drive on. 40 to 50 mm is right for most drives.
- Plan the drainage so that water runs away from the house and does not flow onto the road.
Tools & materials for this project
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Frequently asked questions
How much gravel do I need for a 6m x 5m driveway?
For a 30 m² drive laid 50 mm deep with 20 mm gravel, about 2.5 tonnes with 5% extra, on top of 10.9 tonnes of MOT Type 1 for the sub-base.
How deep should a gravel driveway be?
A layer of 40 to 50 mm of gravel on a compacted sub-base of at least 150 mm of MOT Type 1, over a membrane. A 75 mm layer would take 3.8 tonnes of gravel.
Do I need planning permission for a gravel driveway?
Gravel is a permeable surface, so in England a gravel drive in a front garden does not normally need planning permission. A new access to the highway needs your highway authority. Check with your council.
How many bulk bags of gravel do I need?
A bulk bag holds about 0.8 tonnes. The 30 m² drive takes about 4 bags of gravel and 14 of MOT Type 1.
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Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.