US jobs are imperial, but metric shows up in product data, imported tile and European tools. Knowing the conversions, and the traps, saves expensive mistakes.
Exact factors
| From | To | Multiply by |
|---|---|---|
| inches | mm | 25.4 |
| feet | metres | 0.3048 |
| sq ft | m² | 0.0929 |
| m² | sq ft | 10.764 |
| cu yd | m³ | 0.7646 |
| m³ | cu yd | 1.308 |
| lb | kg | 0.4536 |
| US gallon | litres | 3.785 |
| UK gallon | litres | 4.546 |
The traps
- Tons: a US (short) ton is 2,000 lb (907 kg). A metric tonne is 1,000 kg (2,205 lb). A UK long ton is 2,240 lb.
- Gallons: US gallons are about 17% smaller than UK gallons.
- Nominal timber: a 2×4 is actually 1½" × 3½".
- Sheet sizes: 8×4 ft is 2440 × 1220 mm, but many UK sheets are 2400 × 1200 mm. They're not interchangeable on a stud layout.
- Skips: UK skips are sold in cubic yards. An 8-yard skip holds about 6.1 m³.
Handy approximations
- 1 m ≈ 3 ft 3⅜"
- 1 m² ≈ 10¾ sq ft
- 1 m³ ≈ 1.3 cu yd
- 1 inch ≈ 25 mm (exactly 25.4)
Every TakeoffYard calculator accepts mixed units: pick the unit beside each field, and switch the whole site between US and UK at the top.
This guide is general information for estimating. It is not engineering, legal or tax advice. Check local codes and your inspector for your project.