# US gallons to liters converter

> Convert US gallons to liters (gallons to liters) with the exact factor, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/gallons-to-liters
Subject: Unit converters

A US gallon amount may describe fuel purchased, a tank or a bucket. Converting it to a metric volume helps compare capacities and receipts with a liter-based specification. Imperial gallons are larger, so confirm the receipt or product label says US before using this result.

One US gallon is exactly 3.785411784 liters, so 5 gal is 18.927059 L. To convert gallons to liters, multiply by 3.785411784; to convert back, multiply by 0.2641720524.

The US gallon is defined as exactly 231 cubic inches, which is 3.785411784 L. Because both units are defined exactly, the factor above is exact and the results here carry no conversion error.

## Inputs

- **US gallons (gal)**

## Results

- Liters (L) — main result
- Conversion
- 1 L in US gallons (gal)

## Formula

$$
\text{liters} = \text{US gallons} \times 3.785411784
$$

## Worked examples

### 5 gal to L

- US gallons (gal): 5 gal
- **Liters: 18.92705892 L**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 3 gal to L

- US gallons (gal): 3 gal
- **Liters: 11.356235352 L**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 25 gal to L

- US gallons (gal): 25 gal
- **Liters: 94.6352946 L**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### How many liters is a 5-US-gallon bucket?

Five US gallons is exactly 18.92705892 L. Multiply the gallon capacity by 3.785411784. This is about 18.93 liters of nominal volume; check the marked fill line when measuring an actual quantity.

### How many liters are in a US gallon?

One US gallon is exactly 3.785411784 liters. The US gallon is defined as exactly 231 cubic inches, which is 3.785411784 L.

### How do you convert gallons to liters?

Multiply the number of US gallons by 3.785411784. For example, 5 gal × 3.785411784 = 18.927059 L. To go the other way, divide by 3.785411784.

### How can I estimate gallons to liters without a calculator?

Multiply by 3.8. That is 0.4% high of the exact factor 3.785411784, so 5 gal comes out as 19 L instead of 18.9271.

### How accurate is the US gallons to liters converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “5 gal to L” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)