Ounces vs Fluid Ounces: What Is the Difference?
Fluid ounces measure volume and ounces measure weight. They only line up for water and water-like liquids.
An ounce (oz) is a unit of weight and a fluid ounce (fl oz) is a unit of volume. For water, milk and similar liquids one fluid ounce weighs very close to one ounce, which is why the two get mixed up. For honey, oil or anything dry the numbers drift apart, so use a scale for weight and a liquid measure for fluid ounces.
Weight of 1 fluid ounce and 1 cup
| Ingredient | 1 fl oz | 8 fl oz |
|---|---|---|
| Water | 1.04 oz | 8.36 oz |
| Milk | 1.08 oz | 8.61 oz |
| Heavy cream | 1.05 oz | 8.4 oz |
| Olive oil | 0.952 oz | 7.62 oz |
| Honey | 1.5 oz | 12 oz |
| Maple syrup | 1.42 oz | 11.4 oz |
| All-purpose flour | 0.551 oz | 4.41 oz |
| Granulated sugar | 0.882 oz | 7.05 oz |
Weights and volumes on this page use these grams-per-US-cup densities: water 237 g; milk 244 g; heavy cream 238 g; olive oil 216 g; honey 340 g; maple syrup 322 g; all-purpose flour 125 g; granulated sugar 200 g. Packing, sifting and brand can shift real results by 5–15%, so weigh when a recipe depends on precision.
Common questions
How many ml are in 1 fl oz?
1 fl oz = 29.6 ml.
How many oz are in 1 fl oz of honey?
1 fl oz of honey = 1.5 oz.
How many oz are in 8 fl oz of olive oil?
8 fl oz of olive oil = 7.62 oz.
Is 2 ounces the same as 2 fluid ounces?
Only for water-like liquids. 2 fl oz of water weighs about 2.09 oz, but 2 fl oz of flour weighs just 1.1 oz.