Ounces to Grams Converter
Convert ounces to grams either way ounces are used. Choose US fluid ounces (volume) with a substance — water, whole milk, vegetable oil, flour, sugar, honey, or butter — or plain weight ounces, then enter the amount for grams and kilograms.
Example: with Ounces 8 · Ounce type US fluid ounces (volume) · Substance (for fluid ounces) Water (1.00 g/mL) → Grams: 236.59 g.
- In kilograms0.24 kg
- How it converts8 fl oz × 29.5735 mL × 1 g/mL = 236.59 g
Computed by the calculator below using its default values. Change any input to see your own numbers.
Weight: g = oz × 28.3495 (exact). Fluid: g = fl oz × 29.5735 mL × density. Water is the only common substance where the two nearly agree.
Two different ounces, two different answers
English gave one word to two units. The weight ounce is exactly 28.349523125 grams — a scale reading, no substance required. The fluid ounce is 29.5735 milliliters of volume, and its gram weight depends on what fills it: multiply by the density. Eight fluid ounces (one cup) of water weighs 236.6 g, but the same cup of flour weighs only 125.4 g and a cup of honey 336 g.
Water is the source of the confusion: at about 1 g/mL, one fluid ounce of water weighs 29.57 g, close enough to the 28.35 g weight ounce that people assume they are interchangeable. For oil, flour, sugar, or honey, that shortcut misses by anywhere from 8 to 90 percent — use the substance selector instead.
How it’s calculated
Weight mode: grams = oz × 28.349523125 (NIST exact; 1 lb = 453.59237 g). Fluid mode: grams = fl oz × 29.5735 mL × density (g/mL). Densities used: water 1.00, whole milk 1.03, vegetable oil 0.92, all-purpose flour 0.53, granulated sugar 0.85, honey 1.42, butter 0.955.
Densities are approximate and vary with temperature and packing, so fluid-ounce results are close kitchen estimates rather than lab weights.
What 8 fl oz (one cup) weighs in grams
| Substance | Density (g/mL) | 8 fl oz weighs |
|---|---|---|
| Water | 1.00 | 236.6 g |
| Whole milk | 1.03 | 243.7 g |
| Vegetable oil | 0.92 | 217.7 g |
| All-purpose flour | 0.53 | 125.4 g |
| Granulated sugar | 0.85 | 201.1 g |
| Honey | 1.42 | 336.0 g |
| Butter | 0.955 | 225.9 g |
8 US fl oz = 236.588 mL; grams = mL × density. Densities are approximate typical values.
Common mistakes
- Multiplying fluid ounces by 28.35 — that factor belongs to weight ounces; fluid ounces need 29.5735 × density.
- Ignoring the substance: 8 fl oz of flour weighs about half what 8 fl oz of water does.
- Mixing in the imperial fluid ounce (28.413 mL) from UK labels, which is 4 percent smaller than the US one.
- Assuming oz on a drink label is weight — beverage labels use fluid ounces.
Frequently asked questions
How do I convert ounces to grams?
For weight ounces, multiply by 28.3495: 4 oz = 113.4 g. For fluid ounces, multiply by 29.5735 to get milliliters, then by the substance's density in g/mL: 8 fl oz of water is 8 × 29.5735 × 1.00 = 236.6 g.
How many grams is 8 fl oz of water?
About 236.6 grams. Eight US fluid ounces is 236.588 mL, and water weighs very close to 1 gram per milliliter at room temperature.
Why does my kitchen scale disagree with this for flour?
Because fluid ounces measure volume. A fluid ounce of flour at 0.53 g/mL weighs only 15.7 g, not 28.35 g. If a recipe lists oz for a dry ingredient, it almost always means weight ounces on a scale.
Is 1 oz exactly 28.35 grams?
The weight ounce is exactly 28.349523125 g, fixed by the 1959 definition of the pound as 453.59237 g. The commonly quoted 28.35 is that value rounded.