🛢️ Liters to Gallons Converter (L to US and UK Gallons)

What is the Liters to Gallons Converter?

Liters and gallons both measure liquid volume, but they belong to different measurement systems and, confusingly, there are two different gallons in common use. The liter is a metric unit used almost everywhere in the world, from bottled water labels to car engine specs. The gallon is a customary unit, and the United States uses one size (the US liquid gallon) while the United Kingdom, Canada, and a handful of other countries historically used a different, larger size (the UK or imperial gallon). Because these systems were never designed to line up neatly, converting liters to gallons correctly means knowing which gallon you actually need.

The formula behind every liters to gallons converter is simple division. US gallons = liters divided by 3.78541. So a 20 liter fuel can holds about 5.2834 US gallons, and a 50 liter water tank holds about 13.2086 US gallons. Going the other direction, liters = US gallons multiplied by 3.78541, which is how a US recipe or fuel efficiency figure written in gallons gets translated into the liters that fuel pumps and water meters outside the US actually display.

The detail that trips up the most people is that a gallon is not one universal unit. The US liquid gallon (3.78541 liters) is smaller than the UK imperial gallon (4.54609 liters) by roughly 20 percent. That gap matters a lot for fuel economy: a car rated at 40 miles per US gallon is not the same efficiency as 40 miles per UK gallon, because the UK gallon holds more fuel. This liters to gallons converter always shows both figures side by side, with the US gallon as the primary two-way conversion and the UK gallon as a clearly labeled secondary line, so you are never left guessing which one applies.

Knowing a few common liters to gallons conversions by heart saves repeated trips back to a calculator. 1 liter is about 0.2642 US gallons, 10 liters is about 2.6417 US gallons, and 50 liters (a typical car fuel tank) is about 13.2086 US gallons or 11.0 UK gallons. These benchmarks are useful for reading a European car's fuel tank capacity, checking a water heater or aquarium volume against a US spec sheet, or converting a paint, oil, or chemical container between metric and gallon labeling.

It is also worth knowing that the United States has a second, less common gallon, the US dry gallon (about 4.405 liters), used historically for measuring produce and grain rather than liquids. This tool, like almost every everyday liters to gallons converter, uses the US liquid gallon, since that is the unit printed on fuel pumps, water bottles, milk jugs, and paint cans. If a spec sheet or recipe simply says "gallon" without qualifying it, it almost always means the liquid gallon, but if the source is British, Canadian, or older Commonwealth documentation, double-check whether it means the imperial gallon instead, since silently applying the US liters to gallons factor to an imperial figure will understate the true volume by about 17 percent.

When to use it

• Converting a European or Asian car fuel tank capacity, listed in liters, into US gallons before a US road trip.
• Reading a US water heater, aquarium, or storage tank spec sheet in gallons when you normally think in liters.
• Comparing fuel economy figures given in liters per 100 km against a US miles-per-gallon rating.
• Checking how many liters a 5 US gallon paint can, cooler, or fuel jug actually holds.
• Converting a large-batch recipe or brewing formula between metric liters and US gallon measurements.
• Distinguishing a UK imperial gallon spec from a US gallon spec on imported equipment or tanks.

How to use the Liters to Gallons Converter

1. Type the number of liters into the Liters (L) box.
2. Read the matching US gallons value, which fills in automatically, along with the UK imperial gallon figure underneath.
3. To convert the other way, type a value into the US gallons box instead and the liters figure updates.
4. Use Copy result to save the converted figure, or check the reference table below for common tank and container sizes.

Formula & method

Worked examples

Common liters to gallons conversions

US gallons to liters (reverse conversion)

Common mistakes to avoid

• Mixing up US and UK gallons. A US gallon (3.78541 L) and a UK/imperial gallon (4.54609 L) are not the same, the UK gallon is about 20% larger. Using the wrong one on a fuel tank spec or fuel economy figure gives a badly wrong result, not just a slightly off one.
• Rounding the factor too early. Rounding 3.78541 down to "3.8" or "3.79" before dividing shifts the final answer noticeably over larger volumes like a full tank. Use the full factor and round only the displayed result.
• Dividing instead of multiplying (or the reverse). To go from liters to US gallons you divide by 3.78541; to go from US gallons to liters you multiply. Reversing the operation gives an answer that is off by a factor of roughly 3.79, easy to spot but easy to make.
• Applying a US mpg rating to a UK gallon figure. Fuel economy in "miles per gallon" means different things in the US and UK because the gallons differ in size. A car rated 40 mpg (US) is not equally efficient as one rated 40 mpg (UK, imperial), converting through liters per 100 km avoids the confusion.

Glossary

Liter (L)

A metric unit of volume equal to 1000 milliliters or one cubic decimeter. Used worldwide for fuel, water, and beverage measurement.

US gallon

A US customary unit of liquid volume equal to 3.78541 liters, used for fuel, water, and containers in the United States.

UK (imperial) gallon

A larger gallon used in the UK, Canada, and some Commonwealth countries, equal to 4.54609 liters, about 20% more than a US gallon.

Conversion factor

The fixed number used to convert between two units. For liters and US gallons the factor is 3.78541; for liters and UK gallons it is 4.54609.

Fuel economy (mpg)

Miles traveled per gallon of fuel used. The figure differs between US and UK ratings because the underlying gallon sizes differ.

Quart

A US customary volume unit equal to one quarter of a US gallon, or about 0.94635 liters.

Frequently asked questions