Convert gallon (US) to liter.

About this conversion

US gallons to liters: multiply by 3.78541. Used in fuel economy comparisons, beverage volume, water usage, and shipping/storage capacity.

Formula

L = gal-us × 3.78541

Real-world examples

Reference values

Tips & tricks

• A US gallon is ~17% smaller than a UK (imperial) gallon. A "20 MPG" US car would be "24 MPG" if measured in UK gallons.
• Fuel prices and consumption in Europe are typically L/100km, not MPG. A US 25 MPG car ≈ 9.4 L/100 km.
• Wine and spirits are bottled in 750 mL globally — that's 0.198 US gal or 0.165 UK gal.

Origin & history

The US liquid gallon is 231 cubic inches by historical definition. The UK imperial gallon is different (4.546 L). The two diverged after the US adopted Queen Anne's gallon definition (1707) while the UK reformed to the imperial gallon (1824).

What is a US gallon?

One US gallon equals exactly 3.785411784 liters or 128 US fluid ounces. Gasoline, milk, paint, and most US liquid measurement.

What is a liter?

One liter equals exactly 1,000 milliliters or 0.001 cubic meters. Beverages, fuel, and most everyday liquid measurement worldwide.

What does gal look like in everyday objects?

Some everyday comparisons can make the unit easier to picture.

• 1 gal — a typical jug of milk.
• 5 gal — a standard plastic bucket.
• 20 gal — a typical car fuel tank.

How to convert US gallon to liter

To convert a value from US gallon (gal (US)) to liter (L), apply the conversion factor shown in the formula above. The calculation is the same whether you do it by hand, in a spreadsheet, or with the live converter on this page.

Steps:

1. Take your input value in gal (US).
2. Apply the formula see formula above.
3. The result is your value in L.

For repeated calculations, save the formula in a spreadsheet or use the live converter at the top of this page — it handles the math automatically and displays the result as you type.

Frequently asked questions

How do I convert gal (US) to L?

Apply the formula gal (US) → L shown above, or just type your value into the converter at the top of this page. The result updates instantly.

Which is bigger, gal (US) or L?

This depends on the conversion ratio in the formula. If the factor multiplied by your value gives a larger number, then L is the smaller unit (so it takes more of them to express the same quantity). If the result is smaller, then L is the larger unit.

When would I use gal (US) versus L?

Both units measure volume, so the choice depends on context. Us gallon is typically used for cooking, beverages, fuel, and industrial fluid handling; liter similarly. Most professional fields standardize on one or the other based on regional conventions or technical tradition.

How precise is this gal (US) to L conversion?

The conversion factor shown is the internationally defined exact value (or the best-published approximation if the relationship is irrational, like degrees-to-radians). The live converter on this page uses double-precision floating-point math, accurate to about 15 significant digits — far beyond any practical engineering need.

Is the conversion ratio exact, or an approximation?

Most unit conversions between SI metric units, and between SI and US customary units, have been formally defined as exact values since the 1959 international yard-pound agreement and subsequent SI redefinitions. Exceptions are unit pairs that involve irrational numbers (radians, e.g.) or empirical conversions (like food calories, which depend on temperature). When in doubt, consult the formula at the top of this page.

Related conversions

See also