Fluid Ounces to Cups Converter

How to convert Fluid Ounces to Cups

To convert Fluid Ounces to Cups, multiply the value in Fluid Ounces by 0.125. For example, 5 fl oz = 0.625 cup.

If you need to convert from Fluid Ounces to Cups, the key figure to remember is that one Fluid Ounces equals 0.125 Cups. This page gives you a live calculator, a full reference table, and the underlying formula so you can convert fl oz to cup with complete confidence.

Volume conversions are essential in the kitchen, in science, and in any situation involving liquids or capacity. They're also one of the trickiest areas because US and UK (imperial) measurements share names but differ in size.

Understanding Fluid Ounces and Cups

A US gallon (3.785 liters) is noticeably smaller than a UK gallon (4.546 liters) — about 20% less. The same applies to pints, quarts, and fluid ounces. Cups, tablespoons, and teaspoons are the backbone of recipe measurement, while liters and milliliters dominate scientific and most international contexts. This US/UK split is the single biggest source of error in volume conversion.

How accurate is this conversion?

Volume conversions here use the internationally accepted definitions: the US gallon is exactly 3.785411784 liters and the imperial gallon is exactly 4.54609 liters. Always confirm which system a recipe or specification uses before converting.

All conversion factors on ClearUnits are based on internationally recognised standards (the International System of Units, SI, and official definitions). Factors are reviewed for accuracy and the calculator uses full-precision values, rounding only the displayed result.

Quick reference: common Fluid Ounces to Cups values

The most frequently searched conversions are 1 Fluid Ounces = 0.125 Cups, 5 Fluid Ounces = 0.625 Cups, 10 Fluid Ounces = 1.25 Cups, and 100 Fluid Ounces = 12.5 Cups. The full table further down covers every common value, and the calculator handles any number you need in between.