A solid start for your next project
Block paving calculator: blocks, sub-base and sand
Estimate UK block counts, MOT Type 1 and bedding quantities, edge restraint and jointing-sand packs from product dimensions and entered depths.
Your result
Your plan starts
with a few details.
Enter your project measurements and product details, then calculate to see an estimated take-off.
How it works
Choose the cited nominal 200 × 100 mm module or enter a custom product. The manufacturer’s work dimensions are 198 × 98 mm; the sourced pattern diagrams use a 200 × 100 module. Confirm the actual jointed layout with the supplier.
Choose the laying pattern and intended traffic. The maker restricts the basketweave diagram to foot traffic, so the form rejects that source-backed choice for vehicles. Block quantities remain area-based; no unsupported pattern waste percentage is added. Named-product pack estimates use the published 9.76 m² pack coverage.
Formula
Blocks and layers
Blocks = ceil(area × (1 + allowance %) ÷ (block length × block width)) Layer volume = area × layer depth ÷ 1,000Block dimensions are entered in millimetres. Layer volumes use the area before cutting allowance.
Mass and jointing packs
Layer tonnes = layer volume × supplier density Jointing packs = ceil(order area ÷ entered pack coverage)Use source data for the actual product. Pack coverage depends on block size and joint width.
Worked example
A 20 m² area using 200 × 100 mm blocks has 50 blocks per m² before cuts, or 1,000 blocks before any allowance. At a user-entered 5% cutting allowance, the area calculation gives 1,050 blocks. For an entered 150 mm sub-base depth, volume is 20 × 0.15 = 3 m³. The example does not select a pattern or recommend a base depth.
Assumptions and limits
Marshalls’ September 2024 guide describes 150 mm sub-base as a typical starting point for most domestic applications, while also stating the pavement design depends on ground conditions and expected loading. It illustrates 30–40 mm laying-course sand. These figures are not applied as defaults here.
A block count by face area is not a cutting schedule. Check the actual dimensions and pack sizes, establish falls and drainage, and choose sub-base and bedding depths for the ground and expected use.
Frequently asked questions
Does the chosen paving pattern change the block count?
For the same nominal single-size module, the area-based count stays the same. The chosen sourced pattern supplies its manufacturer diagram and use restriction; basketweave is restricted to foot traffic. Cutting waste remains an explicit project allowance.
Does this calculator choose a sub-base depth?
No. Enter the depth specified for the ground and loads at your project.
Why does the sourced module differ from the block work dimensions?
The selected product lists 198 × 98 mm work dimensions and a nominal 200 × 100 mm laying module. The sourced estimate uses the jointed module; confirm actual joint dimensions and layout with the supplier before using a custom size.
Are joint-sand packs based on block dimensions alone?
No. The estimate uses the coverage you enter for the selected joint sand. Joint width, joint depth and block format affect that coverage.
Sources
- Concrete Block Paving Installation Guide, Marshalls, September 2024Checked on
- Marshalls Standard Block Paving product datasheet, created 17 February 2026Checked on
- Marshalls LP-0008: 200 × 100 stretcher bondChecked on
- Marshalls LP-0010: 200 × 100, 90 degree herringboneChecked on
- Marshalls LP-0001: basket weave, foot traffic onlyChecked on
Specs as of: