How Many Liters in a Gallon
1 US gallon = 3.785 liters — quick conversions and mental math
⚡Quick Answer
1 US gallon = 3.785 liters (round to 3.8). 1 UK gallon = 4.546 liters. Quick trick: multiply gallons by 4, subtract 10%.
Step-by-Step Guide
The Quick Answer
1 US gallon = 3.785 liters (often rounded to 3.8 L). For UK/Imperial gallons: 1 UK gallon = 4.546 liters.
Conversion Formulas
Gallons to liters: multiply by 3.785. Liters to gallons: divide by 3.785. Example: 5 gallons = 5 × 3.785 = 18.93 liters.
Quick Mental Math
For rough estimates: Multiply gallons by 4, then subtract 10%. Example: 3 gallons → 3 × 4 = 12 → 12 - 1.2 = 10.8 L (actual: 11.36 L).
Common Conversions
1 gallon = 3.785 L | 2 gallons = 7.57 L | 5 gallons = 18.93 L | 10 gallons = 37.85 L | 1 liter = 0.264 gallons
Frequently Asked Questions
Why are US and UK gallons different?
The US kept the older Queen Anne wine gallon (231 cubic inches), while the UK adopted the Imperial gallon (277.4 cubic inches) in 1824. The UK gallon is about 20% larger.
How many liters in a half gallon?
Half a US gallon = 1.89 liters (about 1.9 L). This is roughly a standard large water bottle size.
How do I convert liters to gallons?
Divide liters by 3.785. Example: 10 liters ÷ 3.785 = 2.64 gallons. Quick trick: divide by 4 and add 5%.