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Block Paving Calculator — How Many Blocks Do I Need?
Calculate block paving quantities for driveways and patios. Includes herringbone, stretcher bond and basketweave patterns.
Length of area to pave
Width of area to pave
Area not a simple rectangle? An L-shaped area is just two rectangles: measure each one edge to edge and add it as a section. Use three sections for a T or U shape. The calculator adds every section together.
Adds 10% on top of pattern waste
Added to pattern wastage (shown above)
150mm for driveways, 100mm for patios
Sharp sand laying course + kiln-dried jointing sand
Edge restraint around the exposed perimeter
Price per individual block paver
Sharp sand laying course depth (default 35mm)
Jointing sand per m² — typically 3.5 kg/m² (50mm blocks) to 4.5 kg/m² (60mm). Default 4 kg/m² allows for topping up after settlement
Concrete edging block length (default 915mm)
Type 1 MOT ordering density applied to the finished compacted depth — 2,100 kg/m³ is the standard trade figure that allows for ~20% compaction loss
Measured run of edging needed. Leave blank to use the full perimeter of every section. For L or T shapes the automatic figure counts both sides of the line where sections join, and edges against a wall need no restraint, so a measured run avoids over-ordering.
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How We Calculate This
Our block paving calculator works out the number of blocks, sub-base materials, sand, and edging needed for your driveway or patio. It accounts for the extra wastage generated by different laying patterns. If the area is an L or T shape, add each rectangle as its own section: blocks are rounded up within each section (a cut cannot span the join), sub-base and sand use the combined area, and the edging figure adds the full perimeter of every section, an upper bound that over-orders at internal joins, so enter a measured edging run under Advanced options to trim it.
The formula
Blocks = Area × Blocks per m² × (1 + Pattern waste% + Extra waste%)
Sub-base = Area × Depth × 2,100 kg/m³ (2.1 t/m³ ordering density on the finished compacted depth, allowing ~20% compaction loss)
Sharp sand = Area × 0.035m × 1,600 kg/m³ (30-40mm laying course)
Kiln-dried sand = Area × 4 kg/m² (jointing — see range below)
Sub-base depth follows installation guidance in BS 7533-102:2025 (the current code of practice for modular paving, which superseded the withdrawn BS 7533-3 on 31 March 2025): 150mm compacted Type 1 MOT for domestic driveways, 100mm for patios. Kiln-dried jointing sand is typically 3.5 kg/m² for 50mm blocks rising to about 4.5 kg/m² for deeper 60mm joints; the 4 kg/m² default suits the standard 60mm driveway block and leaves a little for topping up after the joints settle. All material rates are adjustable under Advanced options.
Pattern wastage allowances
These are typical trade cut-waste allowances, not fixed standards — the exact figure depends on the shape of your area and the number of edge cuts. The relative ordering is what matters: a 45° herringbone needs the most cuts, stretcher bond the fewest.
- Herringbone 90°: ~5% (fewer edge cuts)
- Herringbone 45°: ~10% (most edge cuts)
- Stretcher bond: ~3% (minimal cuts)
- Basketweave: ~5%
Always confirm against your block manufacturer’s installation guide (e.g. Marshalls, Brett or Tobermore) and add extra for complex shapes, curves or radius cuts.
Frequently Asked Questions
Standard 200 x 100mm block pavers give 50 blocks per m². This is the same regardless of laying pattern — herringbone, stretcher bond, and basketweave all use 50 blocks per m². Cut-waste does vary by pattern though: a 45° herringbone generates more edge cuts, so a typical trade allowance is around 10% extra, while stretcher bond usually needs only about 3-5%. These are rules of thumb, not fixed standards — add more for complex or curved areas.
90° herringbone is the strongest pattern for driveways and areas subject to vehicle traffic. The interlocking pattern distributes load across multiple blocks, preventing tracking and movement. It's a requirement for adoptable roads and recommended by Marshalls and Brett Paving for all driveways.
For driveways, use 60mm thick blocks minimum. 50mm blocks are only suitable for patios and pedestrian areas. The sub-base should be 150mm of compacted Type 1 MOT for domestic driveways, with a 30-40mm sharp sand laying course on top.
For driveways: 150mm of compacted Type 1 MOT sub-base. For patios: 100mm is sufficient. Use our Type 1 Sub-Base Calculator for quantities. The sub-base should be compacted in layers using a plate compactor (wacker plate). Over-excavate by 50mm beyond the paving area to support the edge restraint.
Yes, edge restraint is essential to prevent the blocks from spreading over time. Use concrete edging kerbs (or hidden edge restraint) set in concrete along every exposed edge. Edges that finish against the house or a garden wall are already restrained, and where two sections of an L-shaped area join there is no edge at all, so the calculator’s full-perimeter figure is an upper bound on those shapes: measure your actual open edge and enter it under advanced options for a tighter order. Without restraint, the paving will gradually shift and joints will open up, especially under vehicle loads. Ensure the paved area has adequate drainage fall: use our Drainage Fall Calculator to prevent standing water.
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Last updated: February 2026
Verified against UK standards · estimates only, confirm with your supplier.