The exact factor, and a shortcut you can do in your head
One ounce is exactly 28.349523125 g. That is not a rounded value — it comes straight from the 1959 agreement fixing the pound at 0.45359237 kg, divided by 16. For a quick estimate, multiply the ounces by 28: 4 oz → 112 g, against an exact 113.4. Using 30 is faster but runs about 6 percent high.
Ounces to grams for cooking
| Ounces | Grams | In the kitchen |
|---|---|---|
| 0.5 oz | 14.2 g | 1 tablespoon of butter |
| 1 oz | 28.3 g | a small handful |
| 2 oz | 56.7 g | quarter cup of flour |
| 4 oz | 113.4 g | quarter pound |
| 6 oz | 170.1 g | a chicken breast |
| 8 oz | 226.8 g | half pound |
| 12 oz | 340.2 g | three quarter pound |
| 16 oz | 453.6 g | 1 pound |
Bakers weigh in grams for a reason: a "cup of flour" can range from 120 g to 180 g depending on how it is scooped, while 120 g is always 120 g.
The mistake to avoid
- Ounces are weight, fluid ounces are volume. 1 oz of flour is 28.35 g of mass; 1 fl oz is 29.57 mL of liquid. A recipe listing "8 oz" of a solid means weight, not a measuring cup.
- Gold uses a different ounce. Precious metals are sold by the troy ounce (31.10 g), about 9.7 percent heavier than the 28.35 g cooking ounce here.
Common questions
How many grams is 1 ounce?
1 ounce is 28.35 grams (avoirdupois, the standard ounce). The exact figure is 28.349523125 g.
How many grams is 8 oz?
8 ounces is 226.8 grams, which is half a pound. It is one of the most common weights in meat and baking recipes.
How do I convert ounces to grams quickly?
Multiply by 28, or by 30 for an easier sum that runs slightly high. For 4 oz: 4 x 28 = 112 g, against an exact 113.4.
