Price per Liter to Price per Gallon Converter (US & imperial gallons)

Understanding the price per liter to price per gallon converter — concept and principle

This converter changes a price per litre into a price per US gallon and per imperial (UK) gallon, or the other way round, and can apply an exchange rate to compare with prices in another currency. Travellers comparing fuel prices, importers and anyone reading foreign price lists use it.

A gallon holds more litres — with the default inputs: 6.624 per US gal.

How it is calculated

Price per litre = price per US gallon ÷ 3.785411784 = price per imperial gallon ÷ 4.54609
Price per US gallon = price per litre × 3.785411784
Price per imperial gallon = price per litre × 4.54609
Other currency = price × exchange rate (units of the other currency per one unit of yours)

The principle

A price per gallon is the price per litre multiplied by the litres in a gallon. The US gallon is defined as 231 cubic inches, exactly 3.785411784 L; the imperial gallon is exactly 4.54609 L, about 20% larger. Mixing them is the most common error when comparing US and UK prices. The exchange-rate step simply multiplies by the rate, so enter how many units of the other currency one unit of yours buys.

Worked example

Defaults: 1.75 per litre, exchange rate 1.

Price per litre = 1.75.
Per US gallon = 1.75 × 3.785411784 = 6.624.
Per imperial gallon = 1.75 × 4.54609 = 7.956.
With a rate of 1 the other-currency rows are the same: 1.75, 6.624, 7.956.

Each point is the calculator re-run with only “Price” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Price	Price per litre
0.438	0.438
0.875	0.875
1.31	1.313
1.75	1.75
2.19	2.188
2.62	2.625
3.5	3.5

How to read the result

Compare like with like: US pump prices are per US gallon, UK prices per litre, and older UK figures per imperial gallon. Taxes make up a large and varying share of fuel prices between countries, so differences in price do not show differences in the cost of the fuel itself.

Common mistakes

Using the imperial gallon for US prices or the reverse.
Entering the exchange rate the wrong way round.
Comparing prices that include tax with ones that do not.
Rounding the conversion factor to 3.8 or 4.5.

Keep in mind: Exchange rates change daily. Use a current rate from a reliable source for decisions.

Frequently asked questions

How many litres are in a US gallon?

Exactly 3.785411784 L.

How do I convert a price per gallon to a price per litre?

Divide by 3.785411784 for a US gallon or by 4.54609 for an imperial gallon.

Why are UK gallons bigger?

The imperial gallon was defined separately in 1824 from the US wine gallon, giving a larger volume.

Sources: NIST Special Publication 811 (2008 ed.), Appendix B.9 (US and imperial gallon)

Checked 9 Nov 2026. NIST Special Publication 811 (2008 ed.), Guide for the Use of the International System of Units (SI), Appendix B.9 “Factors for units listed by kind of quantity or field of science” — gallon (U.S.) = 3.785 412 E-03 m³ (defined as 231 in³ with 1 in = 2.54 cm exactly) and gallon (Canadian and U.K. Imperial) = 4.546 09 E-03 m³ (exact).

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