Convert UK Gallons to Liters – Volume Converter
This tool converts volumes expressed in UK (Imperial) gallons to liters. The Imperial (UK) gallon is the traditional gallon used in the United Kingdom and some Commonwealth countries; it differs from the US liquid gallon. Use this converter when you need a quick, standards-informed numeric conversion for documentation, calculation, or unit label purposes.
The conversion implemented here uses the internationally accepted definition of the Imperial gallon expressed in liters. The conversion factor is exact by definition; guidance is included below on practical rounding, measurement uncertainty, and calibration for regulatory or engineering work.
Interactive Converter
Convert between uk gallon (imperial) and liter with precision rounding.
Quick reference table
| UK Gallon (Imperial) | Liter |
|---|---|
| 1 gal_uk | 4.5461 L |
| 5 gal_uk | 22.7305 L |
| 10 gal_uk | 45.4609 L |
| 25 gal_uk | 113.6523 L |
| 50 gal_uk | 227.3045 L |
| 100 gal_uk | 454.609 L |
Methodology
The converter applies the defined relationship between the Imperial (UK) gallon and the liter. By international definition the Imperial gallon equals 4.54609 liters, and the conversion is a direct multiplication: liters = gallons (UK) × 4.54609. This is a fixed mathematical relationship; no empirical estimation is used.
For measurement traceability and legal metrology considerations, reported or recorded volumes should reflect the measurement instrument's calibrated uncertainty. Follow traceability and calibration practices recommended by national metrology institutes and international standards such as NIST guidance and ISO 80000 where applicable. When using converted figures in trade, labeling, or regulatory filings, retain original measurement records and calibration certificates as required by local weights-and-measures authorities.
Worked examples
1 UK gallon → 4.54609 L (exact by definition)
2.5 UK gallons → 11.365225 L → recommend display 11.3652 L (4 decimal places) or 11.37 L (2 decimal places) depending on use
10 UK gallons → 45.4609 L (show as 45.4609 L for technical reporting)
Further resources
Expert Q&A
Is the UK (Imperial) gallon different from the US gallon?
Yes. The UK (Imperial) gallon is larger. One Imperial (UK) gallon equals 4.54609 liters. One US liquid gallon equals 3.785411784 liters. Use the correct gallon type when converting to liters.
Is the conversion factor exact or approximate?
The conversion factor used here (1 UK gallon = 4.54609 liters) is the defined factor and should be treated as exact for unit conversion. However, when converting measured volumes, the overall uncertainty depends on instrument accuracy and calibration.
How many decimal places should I display?
Choose decimal places to reflect measurement uncertainty and regulatory requirements. For general purposes 2 decimal places are typical. For laboratory or engineering work 3–4 decimals or more may be appropriate, but never present more precision than supported by the underlying measurement.
Do I need calibration certificates when using converted volumes for trade?
Yes. For trade, labeling, or compliance, keep original measurement records and calibration documentation as required by local weights-and-measures authorities. Conversion alone does not substitute for traceable calibration.
Can I convert backward from liters to UK gallons with this factor?
Yes. Use the inverse relationship: UK_gallons = liters ÷ 4.54609. Ensure you use the Imperial gallon definition when converting back.
Sources & citations
- NIST: Guide for the Use of the International System of Units (SI) — https://www.nist.gov/pml/special-publication-811
- ISO 80000: Quantities and units (overview) — https://www.iso.org/standard/64973.html
- NIST Weights and Measures and Legal Metrology guidance — https://www.nist.gov/pml/weights-and-measures