Gallons to Liters Converter — Liquid Volume Tool
Convert US gallons to liters instantly with our free gal to L converter. Great for fuel economy, cooking recipes, and international volume measurements.
Formula: liters = gallons (US) × 3.78541
GAL to L Conversion Table
| GAL | L |
|---|---|
| 1 gal | 3.7854 L |
| 5 gal | 18.927 L |
| 10 gal | 37.854 L |
Formula
liters = gallons (US) × 3.78541
Example: 1 gal = 3.7854 L
Frequently Asked Questions
Looking for the reverse? L to GAL Converter
About volume conversion
Volume conversion covers fluid capacities used in cooking, fuel, beverages, and industrial liquids. The biggest source of confusion is that a US gallon (3.785 liters) and a UK gallon (4.546 liters) are genuinely different — a 20% difference — so recipes and fuel economy figures don't port across the Atlantic without care. Other common volume units are liters, milliliters, cups, pints, and fluid ounces (also different between US and UK). Once you know which system a number comes from, conversion is just arithmetic.
How the math works
The liter is defined as exactly 1,000 cubic centimeters (1 dm³). All metric volume units follow directly: 1 mL = 1 cm³, 1 kL = 1 m³. Imperial units are historical but now precisely defined: 1 US fluid ounce = 29.5735 mL, 1 US cup = 236.588 mL, 1 US gallon = 3.78541 L. UK imperial units differ: 1 UK pint = 568.261 mL versus US pint = 473.176 mL. Our converter uses the US variant by default since it's more common in online recipes.
When you'll use this conversion
- Cooking and baking — translating recipes between metric and cups-and-spoons
- Fuel economy (MPG ↔ liters per 100 km)
- Beverages — beer, wine, spirits (draft beer uses pints in UK and US)
- Pharmaceuticals and intravenous fluids (mL is standard)
- Aquariums and pools where water volume matters for chemistry
- Engine displacement in cars (liters vs cubic inches)
A bit of history
The liter originated in 1795 France as a cubic decimeter — one of the cleanest definitions in measurement history. The US gallon descended from the Queen Anne wine gallon (231 cubic inches, set in 1707), while the UK gallon derives from the imperial gallon of 1824 (defined as the volume of 10 pounds of water). This split is why the US switched to smaller gallons when it standardized.
Common mistakes
- Confusing US gallons with UK gallons — a 25% mpg difference between the two
- Treating 1 fluid ounce as 30 mL — it's actually 29.57 mL (US) or 28.41 mL (UK)
- Using weight ounces (28.35 g) when a recipe calls for fluid ounces (volume)
- Assuming 1 liter of liquid always weighs 1 kg — only true for water; oils, honey, alcohol differ
Quick tips
- For mental math: 1 US gallon ≈ 3.8 L, 1 cup ≈ 240 mL, 1 pint ≈ 475 mL (US) or 570 mL (UK)
- Most online recipes use US measurements by default — watch for British sites though
- Motor oil is sold in liters worldwide but may be quarts in the US — check before topping up