What is being measured?
Fuel consumption is fuel volume per distance, while economy is distance per fuel volume. The relationship between them is reciprocal and the gallon convention matters.
Fuel consumption and economy are reciprocal. US and imperial gallons differ; inputs must be positive.
Meaning of imp mpg
uk mpg uses the symbol imp mpg in this library and measures fuel economy. Under the stated reference convention, 1 imp mpg = approximately 282.480936332 L/100 km. This equivalence changes how a known value is written. It does not increase measurement accuracy or establish whether a measurement is appropriate to a real application.
Conversion method
This convention uses a reciprocal transformation. Doubling a consumption quantity halves its reciprocal economy quantity; a constant multiplier is not appropriate.
Worked example
For a known value of 10 imp mpg, the reference conversion gives 28.2480936332 L/100 km. Converting that result back gives approximately 10 imp mpg. This reverse check helps catch a reversed factor, but matching round-trip arithmetic alone does not independently verify a source definition.
Common reference values
| Input (imp mpg) | Reference equivalent (L/100 km) |
|---|---|
| 1 | 282.480936332 |
| 5 | 56.4961872664 |
| 10 | 28.2480936332 |
| 25 | 11.2992374533 |
| 50 | 5.64961872664 |
| 100 | 2.82480936332 |
Compare one imp mpg with other units
| Target unit | Equivalent of 1 imp mpg | Definition guide |
|---|---|---|
| Litres per 100 km (L/100 km) | 282.480936332 | Read definition |
| Miles per US gallon (US mpg) | 0.832674184629 | Read definition |
| kilometers per liter (km/L) | 0.354006189935 | Read definition |
| miles per liter (mi/L) | 0.219969248299 | Read definition |
Precision and common mistakes
- Keep the source and target quantity consistent. A matching symbol is not enough to establish a compatible definition.
- Record the original measurement precision. Showing twelve significant digits in a table does not make a rounded input more precise.
- Check symbol capitalization, prefixes and any regional convention in the source. Use the displayed unit definition rather than a similarly named unit.
- Factors involving repeating fractions or π use finite numerical precision. Round the final answer to the precision justified by your input.
Use a working converter
- Fuel economy converter
- Uk mpg to Miles per US gallon converter
- Uk mpg to Litres per 100 km converter
- Uk mpg to kilometers per liter converter
- Uk mpg to miles per liter converter
Source and verification scope
Examples and tables are computed from the versioned unit definitions used by the linked converters. The source access dates appear below. Computandum is independent of the cited organizations; a citation does not mean that a publisher endorses this page or an actual project.
Sources
- NIST / BIPM: NIST: unit conversion factors ↗ · 2026-10-08