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Block Paving Calculator

Work out paving blocks, sub-base, laying sand and edging for a UK driveway, path or patio.

Inputs
Got a bay window or conservatory? Set it out in Setting Out & Levels → Bays & conservatories. It carves the bay footprint out of the paved area and adjusts the wall run, then hands the corrected figures back here.

15 advanced inputs hidden. Switch to Advanced to fine-tune.

Site context (optional)

Helps tailor algae, weather and longevity advice.

Confidencehigh· 91Complexitymedium· 34

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Area
15
Perimeter m
16m
Blocks required
811
Coverage (with allowance)
16.2
Wastage applied
5%
Cuts allowance
3%
Total allowance
8%
Edge restraint length
16m
Edging units (600 mm)
27
Kiln-dried jointing sand
30kg
Screed (laying) sand
1.2t
Sub Base Depth mm
150mm
MOT Type 1 (theoretical)
5.91t
MOT Type 1 (order qty incl. 10%)
6.5t
MOT bulk bags (order)
8
Bedding Depth mm
50mm
Excavation depth
222mm
Excavation volume
3.33
Spoil volume (bulked)
4.33
Spoil tonnes
5.33t

Heads-up: Block paving lives or dies on its edge restraints — concrete-haunched kerbs or edging blocks on three sides minimum. Laid on a 30 mm sharp-sand bed over compacted MOT Type 1, with kiln-dried sand brushed and vibrated into the joints. Why it matters: For driveways use herringbone (45° or 90°) — it locks under wheel loads. Stretcher bond will rut under cars within a season.

Drainage & falls

Surface drainage is advised here — set a gentle fall away from the house and any structures.

Lay paving with falls of 1:80 (recommended) or 1:60 (minimum) away from buildings.

Why it matters: Smooth paving needs a positive fall to overcome surface tension and shed water before it ponds in low spots.

If ignored: Insufficient falls cause standing water, algae growth, freeze-thaw damage and water tracking back toward the building.

  • Recommended falls: 1:80
  • Edge restraints required
  • Falls 1:80

Quantities pre-filled from your calculation (15.0 m²). Partner links — we may earn a small commission if you buy, at no cost to you.

Quantities include a ~10% waste allowance. Guide prices are indicative UK ranges (materials only, inc. VAT) — always confirm with the supplier before ordering.

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This app provides general UK guidance and material estimates only. It is not legal, planning, engineering or building-control advice. Always confirm requirements with your local planning authority, building control, utility providers, manufacturers or qualified professionals.

How to work out block paving materials

A standard 200 × 100 mm block gives 50 blocks per square metre, so multiply your area by 50 and add about 5% for cuts. Underneath, a driveway needs 150 mm of compacted MOT Type 1 with a 30–40 mm sharp sand laying course. The calculator above sizes blocks, sub-base, sand and edging together so the full build-up is covered in one order.

Block paving build-up (UK)

LayerGuide
Blocks per m² (200 × 100 mm)50 blocks
Sub-base — driveway150 mm compacted
Sub-base — path / patio100 mm compacted
Sharp sand laying course30–40 mm

Restrain every edge with edging kerbs or a concrete haunch, brush kiln-dried sand into the joints, and consider permeable build-ups to avoid draining to the highway.

Pricing a full driveway job?

Set out levels and falls, take off every material and build a compliance-aware quote.

Open Setting Out & Levels

Frequently asked questions

How many block pavers do I need per m²?
A standard 200 × 100 mm block gives 50 blocks per square metre. Multiply your area by 50 and add about 5% for cuts and breakages. The calculator above does this and also sizes the sub-base, laying sand and edging.
What sub-base depth for a block paving driveway?
For a domestic driveway, lay 150 mm of compacted MOT Type 1 sub-base, topped with a 30–40 mm sharp sand laying course. Paths and patios can use 100 mm of sub-base. Poor ground may need extra depth and a geotextile membrane.
How much sand for block paving?
Allow a 30–40 mm sharp sand laying course screeded level over the sub-base, plus kiln-dried sand brushed into the joints at the end. The calculator estimates both from your area.
Do I need edging for block paving?
Yes — block paving must be restrained at every edge with edging kerbs or a concrete haunch, or the blocks will creep and spread under load. Plan edging along all unrestrained perimeters.
Does a block paving driveway need planning permission?
A permeable driveway, or one that drains to a lawn or border rather than the road, usually doesn't need planning permission. An impermeable surface over 5 m² draining to the highway may need it — check current SuDS guidance for your area.

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