Ounces

The ounce is a U.S. customary unit of weight, equal to about 28 grams, used in recipes for butter, chocolate, flour and other dry ingredients.

Ounces: A stainless steel bowl of all-purpose flour resting on a flat digital kitchen scale
  • Measurement, dietary and professional terminology

In American recipes an ounce (abbreviated oz) is a unit of weight. NIST's Metric Kitchen guide gives one ounce by weight as about 28 grams, and an Ohio State University Extension conversion table lists it as 30 grams when rounded, or 28.35 grams more exactly. Sixteen ounces make a pound, which that table gives as about 454 grams, and eight ounces is half a pound.

Bakers meet ounces on package labels and in recipes that call for a four-ounce portion of butter or a few ounces of chocolate. Because the ounce measures weight, it is steadier than a cup, which measures volume and varies with how the ingredient is packed.

The ounce should not be confused with the fluid ounce, which measures volume. A kitchen scale reads ounces of weight, while a liquid measuring cup reads fluid ounces.

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)