Unit Conversion 2026-05-02 5 min read By Konvertibly Team

Litres to Gallons: US vs UK Gallons, Formula and Free Converter

Convert litres to gallons — covers both US and UK gallons, the formula for each, fuel efficiency conversion, and a quick reference table.

Litres to Gallons: US and UK Gallons Explained

The litre (L) is the metric unit of volume used everywhere except the US. Gallons exist in two flavours — the US gallon (3.785 L) and the Imperial gallon used in the UK and Canada (4.546 L). Confusing these leads to significant errors in fuel calculations and recipes.

The Conversion Formulas

US gallons = litres ÷ 3.785
UK/Imperial gallons = litres ÷ 4.546

Quick Reference Table (US gallons)

1 L = 0.264 US gal
10 L = 2.642 US gal
40 L = 10.57 US gal (average car tank)
50 L = 13.21 US gal
100 L = 26.42 US gal

Fuel Efficiency: L/100km vs MPG

This is where confusing US and UK gallons causes the most problems. A car rated at 7 L/100km is roughly 40 MPG (US) or 40.4 MPG (Imperial/UK). The difference between US and UK MPG is about 20% — a car that does 50 MPG (UK) does only ~42 MPG (US).

Common Use Cases

Buying fuel while driving in the US with a metric mindset
Understanding pool and hot tub capacities quoted in gallons
US cooking recipes that call for gallons of liquid (canning, brewing)
Calculating water usage for irrigation or tanks

Convert any volume instantly: Free litres to gallons converter