How many liters are in one gallon?

• A. 1.61 liters
• B. 0.835 liters
• C. 3.785 liters
• D. 2.59 liters

Answer: (C)

Knowing the exact size of a gallon in liters is key. For the US gallon, 1 gallon is 3.78541 liters. You can see this from common subunits: 1 gallon equals 128 US fluid ounces, and 1 liter equals 33.814 US fluid ounces. Dividing 128 by 33.814 gives about 3.785, so one US gallon is roughly 3.785 liters. The other numbers are not correct because they correspond to much smaller volumes (e.g., 1.61 L is about half a gallon; 0.835 L is under a liter; 2.59 L is about 0.68 gallon). If you ever encounter the imperial gallon, that’s about 4.546 liters, larger than the US gallon. The takeaway is that the best match for “how many liters in one gallon” in common contexts is 3.785 liters.