Patio Calculator
Work out how many paving slabs you need for your patio.
Paving slabs
34slabs
- Patio area
- 12 m²
v1.0 · Reviewed September 2026
How this is worked out
The patio area is divided by the area of one slab, multiplied by any waste allowance, then rounded up.
Worked example
- Patio 4 m × 3 m
- Slab 600 × 600 mm
- No waste allowance
12 m² ÷ 0.36 m² = 33.3, rounded up
34 slabs
Assumptions and limits
- Pointing joints are not deducted from the area.
- Cuts at edges and around obstacles normally need a waste allowance of about 5 to 10 per cent.
- Sub-base, laying mortar and jointing compound are separate.