Liters to Gallons Converter — Convert Liters to gallons
Convert liters to gallons with the exact factor, a common-values table, and the formula shown.
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Liters to Gallons Converter
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Liters to Gallons — the Quick Answer
One liter equals 0.264172 US gallons. To convert liters to US gallons, multiply by 0.264172. To go the other way, multiply gallons by 3.785412. These factors are exact by international definition — the US gallon is defined as exactly 231 cubic inches, and the inch is defined as exactly 2.54 cm, which fixes the gallon at exactly 3.785411784 liters. Nothing in this conversion is an approximation.
There is, however, a critical ambiguity you must resolve before converting: which gallon?The US liquid gallon (3.785 L) and the UK/Imperial gallon (4.54609 L) differ by about 20%. A recipe calling for “one gallon” in a British cookbook means roughly 4.5 liters, not 3.8. Fuel economy ratings, container labeling, and industrial specs can all be wrong if you pick the wrong gallon. This page uses the US liquid gallon throughout; a separate note covers the imperial gallon where it matters.
The Liters-to-Gallons Formula
Liters → US Gallons
gallons (US) = liters × 0.264172052exact inverse: liters = gallons (US) × 3.785411784
The factor 0.264172052 is 1 ÷ 3.785411784. The US gallon is defined as 231 cubic inches; the cubic inch is (2.54 cm)³ = 16.387064 mL; so 231 × 16.387064 mL = 3,785.411784 mL = 3.785411784 L. For 5 liters: 5 × 0.264172 = 1.321 US gal.
Source:NIST SP 811 — Guide for the Use of the International System of Units (SI)· National Institute of Standards and Technology
The imperial gallon follows a different chain: it equals exactly 4.54609 liters, set by UK statute in 1985 to align with the SI. So 1 liter = 0.219969 imperial gallons, about 17% less than the US figure. Whenever you see “mpg” in a British car review, the gallon in use is 4.546 L — fuel economy figures will look artificially higher than US mpg by the same 20% ratio.
Common Liter-to-Gallon Values
The table below uses the US liquid gallon (3.785411784 L). Values are rounded to three decimal places; use the formula for intermediate amounts.
US liquid gallon: 1 gal = 3.785411784 L (exact)
Common liters to US gallons conversions
| Scenario | Liters | US Gallons | Imperial Gallons | Everyday reference |
|---|---|---|---|---|
| 1 L | 0.264 gal | 0.220 gal | a standard water bottle | |
| 2 L | 0.528 gal | 0.440 gal | a soda bottle | |
| 4 L | 1.057 gal | 0.880 gal | close to 1 US gallon | |
| 5 L | 1.321 gal | 1.100 gal | a typical oil jug | |
| 10 L | 2.642 gal | 2.200 gal | a small fuel canister | |
| 20 L | 5.283 gal | 4.399 gal | a jerry can | |
| 50 LRecommended | 13.209 gal | 10.998 gal | a medium fuel tank | |
| 100 L | 26.417 gal | 21.997 gal | a large aquarium |
Imperial gallon = liters × 0.219969. The 20% gap between US and imperial gallons is large enough to matter in cooking, fuel, and trade contexts — always confirm which system applies.
Worked Examples
Example 1
Convert 20 liters to US gallons
- Volume
- 20 L
- Factor (US)
- 0.264172 gal/L
Multiply liters by the US conversion factor.
20 × 0.264172 = 5.28344Round to three decimal places.
≈ 5.283 US gal
20 liters = 5.283 US gallons.
The same 20 liters in imperial gallons: 20 × 0.219969 = 4.399 imperial gallons — about 0.88 gallons less. Always note which gallon your context requires.
Example 2
Convert 50 liters (a car fuel tank) to both gallon types
- Volume
- 50 L
US gallons: multiply by 0.264172.
50 × 0.264172 = 13.2086 US galImperial gallons: multiply by 0.219969.
50 × 0.219969 = 10.9985 imp galDifference between the two results.
13.209 − 10.999 = 2.210 gallons
50 L = 13.209 US gal or 10.999 imperial gal. The 2.2-gallon gap illustrates why fuel-economy figures differ between US and UK ratings.
A European car rated at 6 L/100 km converts to about 39.2 US mpg or 47.1 imperial mpg — same fuel efficiency, very different numbers.
How to Use This Converter
- Enter the volume in liters in the field above.
- The result shows US gallons instantly using the exact 0.264172 factor.
- Need imperial gallons or other volume units? Use the all-in-one unit converter with the volume domain.
Common Mistakes
- Using the wrong gallon.The US and imperial gallon differ by 20%. When a UK or Australian source lists gallons, it almost always means the imperial gallon (4.546 L), not the US gallon (3.785 L). Always confirm context.
- Confusing the US liquid gallon with the US dry gallon.There is a rare US dry gallon (4.40488 L) used for grain and agricultural commodities. It is about 16% larger than the liquid gallon. Unless you are measuring dry goods by volume, you want the liquid gallon.
- Rounding the factor to 0.25 or 4.Some shortcuts say “divide by 4 to get gallons” — this overstates the result by about 6% because the true factor is 3.785, not 4. For a 40-liter tank that means a 0.6-gallon error.
- Forgetting fluid ounces in the hierarchy. 1 US gallon = 128 US fluid ounces. If a recipe calls for fluid ounces but you have a liter measure, multiply liters by 33.814 directly rather than converting to gallons first and then multiplying by 128.
Background
Why the US and Imperial Gallon Are Different
The liter has a tidy origin: the metric system, created during the French Revolution, defined it as the volume of one kilogram of water at its maximum density (roughly 4°C). The 1901 third General Conference on Weights and Measures enshrined this as one cubic decimeter — a clean mathematical relationship. When the International Bureau of Weights and Measures (BIPM) published the modern SI Brochure, the liter was recognized as a non-SI unit accepted for use with the SI, equal to exactly 0.001 m³.
The gallon is older and messier. Medieval England used several gallons simultaneously — a wine gallon, an ale gallon, a corn gallon — each calibrated to different trades. The wine gallon of 231 cubic inches became the US gallon when the United States adopted English commercial weights after independence, essentially freezing the wine gallon into law. The UK, meanwhile, standardized its own imperial gallon in 1824 under the Weights and Measures Act, basing it on the volume of 10 pounds of distilled water, which works out to 277.42 cubic inches (4.54609 L). The two nations had thus each picked a different historical gallon and never reconciled.
The US gallon was formally tied to the inch system: exactly 231 cubic inches by federal statute. When the US signed the international yard agreement in 1959, fixing the inch at 2.54 cm, the gallon became fixed in metric terms as well — exactly 3.785411784 liters. The UK later metricated its gallon definition to 4.54609 L exactly by the Weights and Measures Act 1985. Both values are now exact constants, which is why liter-to-gallon conversions carry no rounding error when you use the full precision factor. The enduring legacy of this history is a 20% gap that still confuses fuel economy comparisons, imported appliance specs, and international recipes.
- BIPM SI Brochure — Units and Measurement · Bureau International des Poids et Mesures · 2019
- NIST SP 811 — Guide for the Use of SI, Appendix B (conversion factors) · National Institute of Standards and Technology · 2008
Volume Conversion Terms
Quick reference
Volume & capacity glossary
Liter (L)
The SI non-SI unit of volume equal to exactly one cubic decimeter (0.001 m³). The reference unit for this conversion.
- Originally defined as the volume of 1 kg of water at 4°C, the liter was later given the exact cubic-decimeter definition to remove temperature dependence. One liter of water at standard conditions weighs approximately 1 kg, which is why the two units are so closely associated.
US Liquid Gallon
231 cubic inches = 3.785411784 L (exact). The standard US gallon for liquids and fuel.
- Not to be confused with the US dry gallon (4.40488 L) or the imperial gallon (4.54609 L). The US liquid gallon divides into 4 quarts, 8 pints, or 128 fluid ounces.
Imperial Gallon
4.54609 L (exact). Used in the UK, Canada (informally), and some Commonwealth countries.
- About 20% larger than the US gallon. Fuel efficiency ratings in the UK use imperial mpg, making British cars appear more fuel-efficient than US-rated counterparts even when the underlying consumption is identical.
Quart (qt)
One-quarter of a US gallon = 0.946353 L. Common for milk containers and paint.
- There are also US dry quarts (1.101 L) and imperial quarts (1.137 L). Unless specified, “quart” in US contexts means the liquid quart.
Fluid Ounce (fl oz)
1/128 of a US gallon = 29.5735 mL. Used for beverages, pharmaceuticals, and cooking.
- The US fluid ounce and the imperial fluid ounce are slightly different: the US fl oz is 29.5735 mL, while the imperial fl oz is 28.4131 mL. This matters when comparing US and UK beverage can sizes.
Milliliter (mL)
One-thousandth of a liter = 1 cm³. The everyday small-volume unit in science and medicine.
- Because 1 mL = 1 cm³ exactly, volume and capacity are interchangeable in the metric system. A standard teaspoon in US cooking is about 4.93 mL; a tablespoon is about 14.79 mL.
Cubic Inch (in³)
The volume of a cube with 1-inch sides = 16.387064 mL. The US gallon = 231 in³.
- The cubic inch bridges the US customary and metric systems: because the inch is exactly 2.54 cm, the cubic inch is exactly (2.54)³ = 16.387064 cm³. Multiply 231 of these by 16.387064 to get the gallon’s metric value.
Cubic Decimeter (dm³)
Equal to exactly one liter. The formal SI way to express liter-scale volumes.
- One decimeter is 10 centimeters, so one cubic decimeter is 10 cm × 10 cm × 10 cm = 1,000 cm³ = 1 L. This is why a cube of water 10 cm on a side weighs almost exactly 1 kg.
Related Converters and Tools
For other volume pairs — milliliters, fluid ounces, cubic feet — use the all-in-one unit converter. If you are calculating fuel economy, the gas cost calculator converts fuel prices between per-liter and per-gallon automatically. For aquarium or pool volumes, the unit converter handles liters, US gallons, and cubic feet in one step.
Frequently Asked Questions
The most common questions we get about this calculator — each answer is kept under 60 words so you can scan.
What is the liters to gallons conversion factor?
1 L = 0.264172 US gallons. To convert, multiply your liters value by 0.264172.What is 10 liters in gallons?
10 liters = 2.64 gallons. Multiply 10 by 0.264172 to get the result.How do I convert gallons back to liters?
Divide your gallons value by 0.264172 (or multiply by the reciprocal). The page shows the exact reverse rate.Is this conversion exact or rounded?
The factor itself is exact by international standard; only the displayed result is rounded for readability. Internally full precision is kept.Is the Liters to Gallons converter free?
Yes — free, instant, no signup. All math runs in your browser; nothing is stored.