Imperial Gallons to Liters

What is Imperial Gallons to Liters Converter?

This tool converts UK imperial gallons to liters, important for understanding British fuel economy ratings, working with older UK recipes, and converting specifications between systems. The imperial gallon is significantly larger than its US counterpart.

The Conversion Factor

One imperial gallon equals exactly 4.54609 liters. This is about 20% larger than a US gallon (3.785 L).

Imperial vs US Gallons

• Imperial gallon: 4.546 L (used in UK, Canada for fuel)
• US gallon: 3.785 L (used in United States)
• 1 imperial gallon = 1.2 US gallons

Why This Matters

• Fuel economy: UK mpg figures appear higher than US mpg
• Recipes: Older British cookbooks use imperial measures
• Car specs: UK fuel tank sizes may use imperial gallons
• History: Commonwealth countries historically used imperial

Privacy

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How to Use

Converting imperial gallons to liters is straightforward:

1. Enter the imperial gallon amount
2. View the liter equivalent instantly
3. Use for comparisons or conversions

Quick Estimation

For mental math, multiply by 4.5:

• 10 imperial gallons × 4.5 = 45 liters (actual: 45.46 L)
• This is accurate within 1%

Fuel Economy Comparison

To compare UK and US fuel economy:

• A car rated 50 mpg (imperial) = ~42 mpg (US)
• Multiply UK mpg by 0.833 to get US mpg
• Or divide by 1.2

Common Conversions

• 5 imperial gal = 22.7 L
• 10 imperial gal = 45.5 L
• 15 imperial gal = 68.2 L

Features

Precise Conversion

Uses the exact definition: 1 imperial gallon = 4.54609 liters.

Real-Time Results

Results appear as you type for quick comparisons.

Reference Table

Common imperial gallon to liter conversions:

• 1 imp gal = 4.55 L
• 2 imp gal = 9.09 L
• 5 imp gal = 22.73 L
• 10 imp gal = 45.46 L
• 20 imp gal = 90.92 L

Copy Function

Copy converted values for documentation.

Unit Options

Switch to US gallons or other units using the dropdowns.

Frequently Asked Questions

How many liters in an imperial gallon?

One imperial gallon equals 4.546 liters. This is the UK standard, larger than the US gallon.

What's the difference between imperial and US gallons?

An imperial gallon is 4.546 liters, while a US gallon is 3.785 liters. The imperial gallon is about 20% larger.

Why does UK fuel economy look better than US?

Because UK mpg uses larger imperial gallons. A car getting 40 mpg in the UK would only get 33 mpg using US gallons. The actual fuel efficiency is the same—only the measurement differs.

Is the imperial gallon still used?

Yes, in some contexts. The UK uses imperial gallons for fuel economy ratings (mpg), though fuel is sold by the liter. Canada uses imperial gallons for some purposes. Australia and New Zealand have fully converted to metric.

How do I convert UK mpg to L/100km?

Divide 282.48 by the UK mpg. For example: 50 mpg (imperial) = 282.48 ÷ 50 = 5.65 L/100km.

Why are there two different gallons?

The US kept the older English wine gallon (231 cubic inches) when it became independent. Britain redefined its gallon in 1824 based on the weight of water, creating the larger imperial gallon.