How do I convert Imperial gallon (gal UK) to US gallon (gal)?

1 gal_uk equals 1.20095 gal using SI-based conversion and precise factors.

What is the formula to convert Imperial gallon (gal UK) to US gallon (gal)?

This is a linear unit conversion using a constant factor between units.

How can I share a direct gal_uk to gal result?

Use the shareable URL: https://measurecalc.com/convert/imperial-gallon-to-us-gallon/1

Convert Imperial gallon (gal UK) to US gallon (gal)

Q: Is Imperial gallon (gal UK) to US gallon (gal) conversion exact?

Yes, it uses exact definitions or standardized constants (e.g., 1 in = 25.4 mm).

Category: Volume

Value From To Precision

1.20095 gal

1 gal_uk = 1.20095 gal

High-precision rounding: 6 decimals

How to convert imperial gallon (gal uk) to us gallon (gal)

Volume measures the space a substance occupies. SI uses cubic meters and liters; customary units like gallons, quarts, and pints persist in recipes, fuel, and containers. Accurate volume work often requires temperature and density considerations (e.g., for fuels).

This converter calculates Imperial gallon (gal UK) to US gallon (gal) values by using the correct conversion rule for the Volume category. For linear units, standardized factors are used. For temperature, the calculator applies the proper formula with offsets.

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Quick conversion table

Handy values for Imperial gallon (gal UK) to US gallon (gal). Click a value to open that exact result.

Imperial gallon (gal UK)	US gallon (gal)
1	1.20095
0.5	0.600475
2.5	3.002375
10	12.009499

Conversion formula

Linear unit conversions use standardized factors; many are exact by definition (e.g., 1 in = 25.4 mm, 1 ft = 0.3048 m).

Common mistakes

Mixing US gallons (3.785 L) with Imperial gallons (4.546 L).
Assuming kitchen ‘cup’ equals the same volume in every country.

Unit facts

Imperial gallon (gal UK): The Imperial gallon is exactly 4.54609 L; still used in the UK for beer, milk, and fuel economy.
US gallon (gal): The US gallon is exactly 3.785411784 L; used for fuel, beverages, and bulk liquids.

About Imperial gallon (gal UK)

Imperial gallon (UK)

Exactly 4.54609 L. Still appears in UK fuel economy (mpg) and historical tables.

History: Set by the 1824 Weights and Measures Act; differs notably from the US gallon.

About US gallon (gal)

US gallon (gal)

Exactly 3.785411784 L. Used for fuel, containers, and recipes in the US. Beware of imperial gallon differences.

History: US defined the gallon separately from the British imperial revision; modern value is exact.

Frequently asked questions

How many US gallon (gal) are in one Imperial gallon (gal UK)?

1 Imperial gallon (gal UK) equals 1.20095 US gallon (gal).

Is Imperial gallon (gal UK) to US gallon (gal) conversion exact?

Many unit conversions are exact by definition, while others use standardized conversion constants.

What is the fastest way to convert Imperial gallon (gal UK) to US gallon (gal)?

Enter a value in Imperial gallon (gal UK), choose US gallon (gal) as the target unit, and the calculator will instantly return the result.

Convert Imperial gallon (gal UK) to other units

gal_uk → bbl Barrel (oil, bbl)
gal_uk → ft3 Cubic foot (ft³)
gal_uk → in3 Cubic inch (in³)
gal_uk → m3 Cubic meter (m³)
gal_uk → cup Cup (US)
gal_uk → l Liter (L)

Convert other units to US gallon (gal)

bbl → gal Barrel (oil, bbl)
ft3 → gal Cubic foot (ft³)
in3 → gal Cubic inch (in³)
m3 → gal Cubic meter (m³)
cup → gal Cup (US)
l → gal Liter (L)