Paving Stone Calculator — Pavers, Sand & Base Material
Calculate the number of paving stones, jointing sand and compacted sub-base needed for driveways, patios, paths and garden areas. Enter dimensions and paver size to get a complete material list with waste.
How the paving calculator works
- 1Area = length × width (m²)
- 2Paver count: area ÷ paver face area, with 5–10% waste for cuts and breakage
- 3Laying sand: area × 30 mm depth = m³ of sharp sand, typically 50 kg/bag
- 4Sub-base (MOT Type 1): area × 100–150 mm compacted depth (expands approximately 30% loose)
- 5Jointing sand: linear metres of joints × joint width × depth × density
- 6Round all quantities up; order sub-base and sand by the tonne
Worked example
Patio: 5 × 4 m = 20 m². Paving slabs 600×600 mm. 100 mm MOT sub-base, 30 mm bedding sand.
59 slabs (55.6 base count × 1.05 waste factor, rounded up). Sand: 20 × 0.03 = 0.6 m³ (≈ 900 kg). MOT sub-base: 20 × 0.10 × 1.3 = 2.6 m³ loose (≈ 3.7 tonnes).
Frequently asked questions
How many paving slabs do I need for a 20 m² patio?
For 600×600 mm slabs (0.36 m² each): 20 ÷ 0.36 = 55.6 base count × 1.05 waste = 58.4, rounded up to 59 slabs. For 450×450 mm slabs: 101 slabs. Use the calculator above for other sizes.
How deep should a paved area be excavated?
For a pedestrian patio: 150–200 mm total depth (100 mm sub-base + 30–50 mm sand + slab thickness). For a vehicle driveway: 250–300 mm total with 150 mm compacted MOT Type 1.
What sand should I use for laying paving?
Sharp (coarse) sand for the bedding layer. Kiln-dried silver sand for brushing into joints after laying. Never use building sand for bedding — it retains moisture and can cause frost heave.
How much MOT sub-base do I need per m²?
At 100 mm compacted depth, allow 0.18 tonne per m² (compacted density ≈ 1.8 t/m³). For 20 m²: approximately 3.6 tonnes. Order as loose material — it compacts by about 30%.
Can I lay paving on soil without a sub-base?
Not for any permanent installation — soil settlement will cause cracking and trip hazards. Even a simple garden path needs at least 75 mm of compacted hardcore. For driveways, 150 mm MOT Type 1 is the minimum.