Gallons to Liters Converter
Convert US gallons to liters instantly with our free online calculator. Essential for fuel economy comparisons, cooking conversions, aquarium volumes, and international recipes.
Conversion Formula
| Conversion | Formula | Example |
|---|---|---|
| US gal to L | gal × 3.78541 | 10 gal = 37.85 L |
| L to US gal | L ÷ 3.78541 | 37.85 L = 10 gal |
| UK gal to L | gal × 4.54609 | 10 gal = 45.46 L |
US vs Imperial Gallon
| Type | Liters | Difference |
|---|---|---|
| US Gallon | 3.78541 L | Standard in USA |
| UK/Imperial Gallon | 4.54609 L | 20% larger |
Quick Reference Table
| US Gallons | Liters | Common Use |
|---|---|---|
| 1 gal | 3.79 L | Milk jug |
| 2.5 gal | 9.46 L | Small container |
| 5 gal | 18.93 L | Jerry can |
| 10 gal | 37.85 L | Aquarium |
| 15 gal | 56.78 L | Car fuel tank |
| 20 gal | 75.71 L | Large tank |
| 55 gal | 208.2 L | Standard drum |
Fuel Economy Conversion
Converting MPG to L/100km:
| MPG (US) | L/100km | Efficiency |
|---|---|---|
| 15 | 15.68 | Poor |
| 20 | 11.76 | Below average |
| 25 | 9.41 | Average |
| 30 | 7.84 | Good |
| 40 | 5.88 | Very good |
| 50 | 4.70 | Excellent |
Conversion Code Example
``javascript
function gallonsToLiters(gallons, isImperial = false) {
const factor = isImperial ? 4.54609 : 3.78541;
return gallons * factor;
}
function litersToGallons(liters, isImperial = false) {
const factor = isImperial ? 4.54609 : 3.78541;
return liters / factor;
}
function mpgToL100km(mpg) {
return 235.215 / mpg;
}
// Examples
console.log(gallonsToLiters(10)); // 37.8541
console.log(mpgToL100km(30)); // 7.84
``
Aquarium Sizes
| Gallons | Liters | Tank Type |
|---|---|---|
| 5 gal | 19 L | Betta tank |
| 10 gal | 38 L | Small community |
| 20 gal | 76 L | Medium tank |
| 40 gal | 151 L | Large tank |
| 75 gal | 284 L | Show tank |
| 125 gal | 473 L | Very large |
Cooking Measurements
| US Volume | Liters |
|---|---|
| 1 cup | 0.237 L |
| 1 pint | 0.473 L |
| 1 quart | 0.946 L |
| 1 gallon | 3.785 L |
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 gal with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 gal becomes | Error |
|---|---|---|---|
| 0 | 4 | 548 | 5.6688% |
| 1 | 3.8 | 520.6 | 0.3854% |
| 2 | 3.79 | 519.23 | 0.1212% |
| 3 | 3.785 | 518.545 | 0.0109% |
| 4 | 3.7854 | 518.6 | 0.0003% |
The right number of significant figures is set by your input, not by the converter. If you measured gallons to three significant figures, the answer in liters is only good to three — writing more digits claims precision the measurement never had.