How it calculates
One canonical path prevents inconsistent answers
Every supported unit stores a verified size in milliliters. A conversion first expresses the starting amount in milliliters, then divides by the destination unit’s milliliter value. Tables elsewhere on the site use the same dataset.
result = value × from-unit mL ÷ to-unit mLThe displayed answer uses smart significant-digit formatting. The calculator marks a value as approximate when the visible number has been rounded. It keeps more precision internally than is normally useful on screen.
System guardrails
“Gallon” and “fluid ounce” are not universal sizes
The selector never says only “gallon,” “pint,” or “fluid ounce.” It identifies US or Imperial because these systems use different physical volumes.
Worked paths
Three examples
2 US gallons to cups
2 × 3,785.411784 ÷ 236.5882365 = 32 cupsInside one exact system, the familiar whole-number relationship appears.
5 liters to US gallons
5,000 ÷ 3,785.411784 ≈ 1.320860262 US galThe visible decimal is rounded because the quotient continues.
12 Imperial fluid ounces to milliliters
12 × 28.4130625 = 340.95675 mLThis uses the Imperial fluid ounce—not the larger US fluid ounce.
Supported definitions
Units in this converter
231 cubic inches; 4 US liquid quarts
1/4 US gallon; 2 US liquid pints; 32 US fluid ounces
1/8 US gallon; 2 US cups; 16 US fluid ounces
8 US fluid ounces
1/128 US gallon; 1/16 US liquid pint
1/2 US fluid ounce; 3 US teaspoons
1/6 US fluid ounce; 1/3 US tablespoon
1 cubic decimeter; 1,000 milliliters
1 cubic centimeter; 1/1,000 liter
4.54609 liters; 8 Imperial pints; 160 Imperial fluid ounces
1/8 Imperial gallon; 20 Imperial fluid ounces
1/160 Imperial gallon; 1/20 Imperial pint
Constants last verified . See the measurement sources and correction process.