Cups to Fluid Ounces Converter

How to convert Cups to Fluid Ounces

To convert Cups to Fluid Ounces, multiply the value in Cups by 8. For example, 5 cup = 40 fl oz.

If you need to convert from Cups to Fluid Ounces, the key figure to remember is that one Cups equals 8 Fluid Ounces. This page gives you a live calculator, a full reference table, and the underlying formula so you can convert cup to fl oz 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 Cups and Fluid Ounces

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 Cups to Fluid Ounces values

The most frequently searched conversions are 1 Cups = 8 Fluid Ounces, 5 Cups = 40 Fluid Ounces, 10 Cups = 80 Fluid Ounces, and 100 Cups = 800 Fluid Ounces. The full table further down covers every common value, and the calculator handles any number you need in between.