MOT Type 1 Calculator UK
Calculate how much MOT Type 1 sub-base you need in tonnes and bulk bags for patios, driveways, paths and garden projects. Includes a compaction factor so your order covers the compacted depth you actually need.
Enter your dimensions
Enter the compacted depth you need. Typical: 100mm (patio), 150mm (driveway)
Advanced: override density (optional)
Leave blank to use default 2.1 t/m³. Adjust if your supplier specifies a different figure.
Covers cuts, breakages and uneven ground. 10% is a typical starting point.
MOT Type 1 estimate
Enter length, width and depth to see your MOT Type 1 estimate
How to calculate MOT Type 1
The volume calculation is length × width × compacted depth. The important extra step with MOT Type 1 is applying a compaction factor - because loose aggregate compacts significantly when rolled or plate-compacted.
Our calculator does this automatically. Enter the compacted depth you need (e.g. 100mm for a patio), and we calculate how much loose material to order, including the compaction factor and your wastage allowance.
The result is given in tonnes (the standard ordering unit for bulk aggregate in the UK) and converted to a bulk bag estimate.
Worked example - 4m × 3m patio sub-base at 100mm
Typical MOT Type 1 depths
| Use | Depth | Notes |
|---|---|---|
| Garden path (pedestrian) | 75mm | Minimum for light foot traffic |
| Patio (pedestrian) | 100mm | Most common for domestic patios |
| Driveway (car) | 150mm | Standard for single-vehicle residential |
| Driveway (van / lorry) | 200mm+ | Seek specialist advice for heavy vehicles |
Related calculators
Calculate MOT Type 1, sharp sand, grano dust, weed membrane and pins for an artificial grass base.
Work out sub-base quantities for patios, driveways and garden paths.
Work out how much concrete you need for a shed base, garage base or garden room.
Calculate sharp sand in tonnes, kg and bags for patios, paving slabs, artificial grass and screeding.
Frequently asked questions
Planning estimates only
These results are estimates for planning purposes only. Actual material quantities can vary based on site conditions, compaction, wastage, product size, installation method and supplier guidance. For structural, safety-critical or regulated work, always consult a qualified professional.