Convert Imperial Gallon to US Gallon


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About our Imperial Gallon to US Gallon Converter Tool


Quick answer

Multiply imperial gallon by 1.20095 to convert to US gallon (1 imperial gallon = 1.20095 US gallon).

Key facts

  • This is a Imperial (UK) to US customary conversion|The conversion factor 1 imperial gallon = 1.20095 US gallon is a standard rounded approximation|Bidirectional: also converts US gallon back to imperial gallon|Runs entirely in your browser via JavaScript, no data sent to a server|Free with no usage limit

What is this tool?

This tool converts a volume value from imperial gallon to US gallon and back again, using a Imperial (UK) to US customary conversion factor. It is intended for anyone -- students, engineers, cooks, or shoppers -- who needs a fast, accurate volume conversion without doing the arithmetic by hand.

How to use it

Type a value into the imperial gallon field to see its US gallon equivalent appear instantly, or type into the US gallon field to get the imperial gallon equivalent. Both fields update live as you type, and the Clear button resets them.
  1. Enter a numeric value in the imperial gallon field.|The equivalent in US gallon appears instantly in the second field.|To convert the other way, type a value into the US gallon field instead.|Use the Clear button to reset both fields.

Example

Example: entering 5 imperial gallon returns 6.0047 US gallon (since 1 imperial gallon = 1.20095 US gallon).

How it works

US gallon = imperial gallon x 1.20095 (1 imperial gallon = 1.20095 US gallon; equivalently 1 US gallon = 0.832674 imperial gallon). This factor is a standard rounded approximation for the Imperial (UK) to US customary relationship between these two units. The page applies it directly to your typed value using JavaScript, in both directions.

Common use cases

Converting recipe or beverage measurements between metric and US/Imperial systems.|Checking a container, tank, or shipping volume listed in a different unit system.|Academic, engineering, or scientific volume calculations.|Comparing product volumes listed in different units while shopping online.

Benefits

Instant, free, and requires no signup or installation; works from any device with a browser; uses the standard, verifiable conversion factor rather than an approximation where the underlying relationship is exact.

Limitations

This conversion uses a standard rounded constant (1 imperial gallon = 1.20095 US gallon), so extremely high-precision calculations may show tiny rounding differences; always confirm whether a US or Imperial gallon is meant, since the two differ by about 20 percent and are not interchangeable.

Privacy & your data

This converter runs entirely in your browser. The value you type is processed locally by JavaScript and is not sent to the A2Z Tools server, stored in a database, or shared with any third party.

Frequently asked questions

How many US gallon are in 1
1 imperial gallon equals 1.20095 US gallon. This converter applies that exact ratio to whatever value you enter.
Is this conversion exact or approximate?
It's a standard rounded approximation. The factor 1.20095 is accurate to the precision shown, but very high-precision scientific work should use a more decimal-rich constant if needed.
Does this use US or Imperial units?
This conversion is specifically between US customary and Imperial (UK) units, which are NOT interchangeable -- an Imperial gallon is about 20% larger than a US gallon.
Can I convert US gallon back to imperial gallon with this tool?
Yes. The tool is bidirectional -- enter a value in either the imperial gallon field or the US gallon field and the other field updates automatically (1 US gallon = 0.832674 imperial gallon).

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