Fluid ounces

The fluid ounce is a U.S. customary unit of volume, equal to two tablespoons or about 30 milliliters, used for liquid ingredients.

Fluid ounces: A clear glass liquid measuring cup filled with milk to a marked line
  • Measurement, dietary and professional terminology

A fluid ounce (fl oz) measures volume, not weight. NIST's Metric Kitchen guide gives one fluid ounce as about 30 milliliters and notes that a tablespoon is half a fluid ounce. Extension conversion tables agree: two tablespoons make one fluid ounce, a quarter cup is two fluid ounces, and a cup is eight fluid ounces, or about 237 milliliters. Two cups make a pint of 16 fluid ounces, and four cups make a quart of 32 fluid ounces.

Bakers use fluid ounces for milk, cream, water, oil and other liquids, usually measured in a clear liquid measuring cup read at eye level.

The name causes confusion with the ounce, a unit of weight. For water the two are close, but for thick or light ingredients such as honey or flour a fluid ounce and an ounce are not the same thing, so recipes must say which one they mean.

Related entries

Sources

Written by VanillaGoods in our own words from these sources. Last reviewed October 15, 2026.

  1. Metric Kitchen: Cooking Measurement Equivalencies, NIST (U.S. National Institute of Standards and Technology)
  2. Kitchen Measurement Conversion Tables, Ohio State University Extension (4-H)