Paving calculator
Estimate paving slabs, MOT Type 1 sub-base and sharp sand for patios, pathways and driveways. Enter your area and slab size and we'll work out the quantities in tonnes, bulk bags and slab counts.
Patio area
12 m²
Slabs needed
37 slabs
Sub-base (MOT Type 1)
1.2 m³
Bedding sand
0.6 m³
How the patio calculator works
Type in the patio length and width in metres, plus the slab size you are using. The calculator returns the number of slabs you need (including a 5–10% cutting allowance), the volume of MOT Type 1 sub-base in tonnes for a 100–150 mm compacted layer, and the volume of sharp bedding sand for a 25–50 mm screeded bed.
Common slab sizes and coverage
- 600 × 600 mm patio slabs – roughly 2.78 slabs per m².
- 450 × 450 mm slabs – roughly 4.94 slabs per m².
- Indian sandstone 600 ×900 mm project packs – about 1.85 slabs per m².
- Block paving 200 × 100 mm – exactly 50 blocks per m².
Sub-base and bedding depth
For a domestic patio on well-drained ground, 100 mm of compacted MOT Type 1 is enough. Add a further 50 mm for driveways or poor ground. Sharp bedding sand should be 25–50 mm once screeded — only lay as much as you can pave in a session so the bed stays workable. Jointing compound or dry mortar is sold separately in 15 kg tubs for roughly 5–8 m² of 600 mm paving.
Common projects
Quick reference quantities for the jobs we get asked about most. Enter your own measurements in the calculator above for an exact figure.
4 m × 5 m patio
Using 600 × 600 mm slabs: roughly 36 slabs, 2 tonnes of MOT Type 1 and 0.5 tonnes of sharp bedding sand.
3 m × 6 m driveway
Heavy-duty slabs need roughly 18 slabs, 2.5 tonnes of MOT Type 1 and 0.6 tonnes of bedding sand.
1.2 m × 10 m garden path
Using 450 × 450 mm slabs: roughly 30 slabs plus sub-base and bedding for the full length.
2 m × 3 m utility area
Approximately 10 large-format slabs, 1 tonne of MOT Type 1 and 0.25 tonnes of bedding sand.
Frequently asked questions
- How deep should the MOT Type 1 sub-base be?
- Allow 100 mm for patios on well-drained ground and 150 mm for driveways or areas with poor drainage.
- How much bedding sand do I need?
- A screeded bed of 25–50 mm sharp sand is typical. The calculator returns the volume in tonnes based on your area.
- What wastage should I allow for paving?
- Order 10% extra slabs to cover cuts, breakages and future repairs.
- Can I use this calculator for block paving?
- Yes. Enter the block size — a standard 200 × 100 mm block gives exactly 50 blocks per m².
- Do I need edge restraints?
- Yes. Driveways, raised patios and any paved surface subject to vehicle or foot traffic should have edge restraints to prevent spreading.