VOLUME CONVERSION
Imperial gallons to US gallons converter
Convert imperial gallons to us gallons instantly.
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No regional currency, unit or language profile is applied. This choice does not convert values or change formulas, results, routes or legal guidance.
1 imp gal equals
1.200949925505 galInstant imperial gallons to us gallons conversionCalculated locally in your browser using the stated conversion formula.Imperial gallons to US gallons conversion guide
Use this calculator when comparing measurements, checking specifications, planning travel, preparing materials or reading information published in another unit system. Enter any value above to receive the converted result immediately.
Worked example: 10 imp gal equals 12.00949926 gal. The displayed result is rounded for readability while the calculator retains full numeric precision.
About Imperial gallons and US gallons
- Imperial gallons
- A UK imperial gallon equals exactly 4.54609 litres. Imperial or US customary measurement, depending on the unit.
- US gallons
- A US liquid gallon equals exactly 3.785411784 litres. Imperial or US customary measurement, depending on the unit.
Precision and common mistakes
The imperial-gallon relationship is exact. The US liquid gallon relationship is exact. The calculator keeps the full catalogued factor internally and rounds only the displayed value.
- An imperial gallon is larger than a US liquid gallon.
- A US gallon is smaller than a UK imperial gallon.
- Keep the original value and unit together when copying a result, especially when specifications use several measurement systems.
Imperial gallons to US gallons table
1 imp gal1.20094993 gal
5 imp gal6.00474963 gal
10 imp gal12.00949926 gal
25 imp gal30.02374814 gal
50 imp gal60.04749628 gal
100 imp gal120.09499255 gal
Frequently asked questions
How do I convert imperial gallons to us gallons?
Multiply the imperial gallons value by 1.20094992550. For example, 10 imp gal equals 12.00949926 gal.
Is this Imperial gallons to US gallons conversion accurate?
The calculator uses the stated conversion relationship and keeps full internal precision before formatting the displayed answer. For regulated or safety-critical work, confirm the required rounding standard.
Can I use this converter on a phone?
Yes. The calculator is responsive, keyboard accessible and performs the conversion locally in a modern browser without requiring an account.
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Verification and calculation details
- Purpose
- Imperial gallons to US gallons converter
- Variables and units
- Use the labelled fields and units shown in the calculator. Results use those units unless a conversion is stated.
- Formula and method
- The exact formula and worked example are shown below. Deterministic formula executed locally in the browser.
- Assumptions
- Only entered values and stated assumptions are included. Local fees, rules and professional requirements are excluded unless explicitly shown.
- Engine version
- 1.0.0
- Production verification baseline
- Release 63 · source
998803f - Verification run
release-v63-2026-09-20- Last verified
- — Automated release checks passing
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How this calculator works
US gallons = Imperial gallons × 1.20094992550.
Important notes
Results are estimates based on the values entered. Confirm rates, prices, units and professional requirements that apply in your location. Review the Answer Atlas Calculation Standard and corrections policy for formula, privacy and correction rules.