# Gallons to Liters Converter

Convert US gallons to liters instantly. Also shows milliliters, quarts, and cups. Exact factor: 1 US gal = 3.78541 L.

## What this calculates

Convert any volume from US gallons to liters using the exact conversion factor: 1 US gallon = 3.785411784 liters. This converter also displays milliliters, quarts, and cups for kitchen and everyday use.

## Inputs

- **Volume in Gallons (US)** (gal) — min 0 — Enter a volume in US gallons.

## Outputs

- **Liters** (L) — Volume in liters.
- **Milliliters** (mL) — Volume in milliliters.
- **Quarts** (qt) — Volume in quarts.
- **Cups** (cups) — Volume in US cups.

## Details

The US gallon is a unit of volume in the United States customary system, while the liter is the standard metric unit for volume. The US liquid gallon is defined as exactly 231 cubic inches, which equals 3.785411784 liters. Note: the US gallon is different from the Imperial (UK) gallon, which is larger at 4.54609 liters.

Common Gallon to Liter Conversions

US Gallons
Liters
Context

0.25 gal
0.946 L
1 quart

0.5 gal
1.893 L
Half gallon

1 gal
3.785 L
Base conversion

2 gal
7.571 L
Large jug

5 gal
18.927 L
Water cooler bottle

10 gal
37.854 L
Fish tank

15 gal
56.781 L
Car fuel tank (small)

20 gal
75.708 L
Car fuel tank (large)

US vs Imperial Gallons: A US gallon (3.785 L) is about 83% of an Imperial gallon (4.546 L). This difference matters when reading fuel economy figures from different countries. A car rated at 30 mpg (US) would be rated at about 36 mpg (Imperial).

## Frequently Asked Questions

**Q: How many liters are in a US gallon?**

A: One US liquid gallon equals exactly 3.785411784 liters. This is defined from 1 US gallon = 231 cubic inches, and the liter being 1000 cubic centimeters.

**Q: What is the difference between a US gallon and an Imperial gallon?**

A: A US gallon equals 3.785 liters, while an Imperial (UK) gallon equals 4.546 liters. The Imperial gallon is about 20% larger. This distinction is important when comparing fuel prices or consumption figures between the US and UK.

**Q: How many cups are in a gallon?**

A: There are 16 US cups in a US gallon. The breakdown is: 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces.

**Q: How do I convert gallons to liters for cooking?**

A: Multiply gallons by 3.785. For quick estimation, 1 gallon is a little less than 4 liters. One quart (1/4 gallon) is close to 1 liter (actually 0.946 L), making quart-to-liter a convenient near-1:1 approximation.

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Source: https://vastcalc.com/calculators/conversion/gallons-to-liters
Category: Conversion
Last updated: 2026-04-21