18 US MPG to UK MPG
| 18 MPG (US) | = | 21.6 MPG (UK / Imperial) |
| 18 MPG (US) | = | 13.1 L/100km |
| 18 MPG (US) | = | 7.65 km/L |
How to Convert US MPG to UK MPG
The conversion is linear — the difference is entirely in the size of the gallon, not in the miles.
- MPG (UK) = MPG (US) × 1.20095042
The factor 1.20095 is the exact ratio between the Imperial gallon (4.54609 L) and the US gallon (3.785411784 L).
Applying the formula to 18 MPG (US): 18 × 1.20095 = 21.6 MPG (UK).
Is 18 MPG (US) good?
18 MPG (US) is considered Below average — typical of full-size SUVs and pickup trucks. In Imperial terms, that’s 21.6 MPG (UK). In metric terms, 13.1 L/100km or 7.65 km/L.
Need a different value? Use our US MPG to UK MPG Converter.
Similar Conversions
| MPG (US) | MPG (UK) | L/100km |
|---|---|---|
| 13 MPG | 15.6 | 18.1 |
| 14 MPG | 16.8 | 16.8 |
| 15 MPG | 18.0 | 15.7 |
| 16 MPG | 19.2 | 14.7 |
| 17 MPG | 20.4 | 13.8 |
| 19 MPG | 22.8 | 12.4 |
| 20 MPG | 24.0 | 11.8 |
| 21 MPG | 25.2 | 11.2 |
| 22 MPG | 26.4 | 10.7 |
| 23 MPG | 27.6 | 10.2 |
Related Fuel Economy Converters
Conversion factors verified against NIST, BIPM
Based on SI definitions (BIPM).
Last reviewed: March 2026
