UK block paving calculator
Block Paving Sand Calculator UK
Estimate sharp sand or bedding sand for block paving. A 50 mm sand bed with 10% allowance needs about 0.55 m3 for 10 m2 or 1.10 m3 for 20 m2.
Quick answer
- 10 m2 at 50 mm bedding depth needs about 0.55 m3 of sand.
- 20 m2 at 50 mm bedding depth needs about 1.10 m3 or 1.76 tonnes.
- Do not use extra sand to hide a low or poorly compacted sub-base.
Interactive estimator
Block paving bedding sand calculator
Example: 10 m2 at 50 mm needs about 0.55 m3 or 0.88 tonnes of bedding sand, equivalent to 2 x 850 kg bulk bags.
Enter area, screeded depth, and allowance, then confirm sharp-sand density with the merchant.
Block paving sharp sand estimates
| Area | Sand bed | Cubic metres | Tonnes | 850 kg bulk bags |
|---|---|---|---|---|
| 10 m2 | 50 mm | 0.55 m3 | 0.88 t | 2 |
| 20 m2 | 50 mm | 1.10 m3 | 1.76 t | 3 |
| 30 m2 | 50 mm | 1.65 m3 | 2.64 t | 4 |
| 40 m2 | 50 mm | 2.20 m3 | 3.52 t | 5 |
Assumes 10% allowance and 1.6 tonnes per cubic metre sand density. Check your local supplier's density.
Sharp sand vs kiln dried sand
Sharp sand or grit sand is used as the bedding layer under block paving. Kiln dried sand is normally brushed into joints after the blocks are laid.
This page estimates the bedding layer. Use a polymeric or joint sand product chart when estimating joint fill material.
Calculate sand for block paving
Area x sand bed depth gives cubic metres before allowance. A 20 m2 area at 50 mm is 1.0 m3 before allowance and about 1.10 m3 after adding 10%.
Keep the bedding layer consistent. If levels are wrong, fix and compact the sub-base before screeding sand.
Helpful next step
Use the bedding sand calculator for custom area and depth. Use the UK sub-base page when you need MOT Type 1 below the sand layer.