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Imperial gallons to US gallons (gal (UK) to gal (US))

Convert imperial gallons to US gallons: 1 gal (UK) = 1.20095 gal (US). Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

Formula

1 gal (UK) = 1.20095 gal (US)

US gallons = imperial gallons × 1.200949926 — reverse: imperial gallons = US gallons × 0.8326741846

The factor is derived from the SI definitions of both units (base unit: L) as listed in NIST SP 811; results on this page are shown to 6 significant figures, the API returns up to 12.

Worked examples

Imperial gallons to US gallons conversion table

Imperial gallons (gal (UK))US gallons (gal (US))
11.20095
22.4019
33.60285
44.8038
56.00475
67.2057
78.40665
89.6076
910.8085
1012.0095
1518.0142
2024.019
2530.0237
3036.0285
4048.038
5060.0475
7590.0712
100120.095
200240.19
250300.237
500600.475
10001200.95

FAQ

How many US gallons are in one imperial gallon?

1 gal (UK) = 1.20095 gal (US). The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

What is the formula to convert imperial gallons to US gallons?

Multiply the value in imperial gallons by 1.200949926: US gallons = imperial gallons × 1.200949926. For example, 5 gal (UK) = 6.00475 gal (US).

How do I convert US gallons back to imperial gallons?

Multiply by the inverse factor 0.8326741846 (imperial gallons = US gallons × 0.8326741846), or use the US gallons-to-imperial gallons page.

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