How to Convert Ounces to Grams
Mass · Last updated: July 2025
In US customary units, the avoirdupois ounce (oz) used for most grocery and shipping weight equals 28.349523125 grams. This is different from the fluid ounce (volume) and the troy ounce (precious metals).
The formula
Grams = ounces × 28.3495
Ounces = grams ÷ 28.3495
Sixteen ounces make one pound, so 1 lb = 453.592 g.
Common weights
| From | To |
|---|---|
| 1 oz | 28.35 g |
| 4 oz | 113.4 g |
| 8 oz | 226.8 g |
| 16 oz (1 lb) | 453.6 g |
| 100 g | 3.527 oz |
| 500 g | 17.637 oz |
Cooking and nutrition
US nutrition labels and recipes use ounces; metric recipes use grams. Baking benefits from a kitchen scale in grams for consistency. A “12 oz bag of chips” is about 340 g net weight.
Not the same ounce
- Fluid ounce (fl oz): volume—use volume conversion, not grams.
- Troy ounce: about 31.103 g—used for gold and silver.
- International avoirdupois ounce: what this guide covers.
Common mistakes
- Converting fl oz of water to grams by using the mass ounce factor (happens to be close for water only—fails for oil or flour by volume).
- Confusing net weight oz with fluid oz on packaging.
References
Convert oz and g on tounits.com — try 4 oz or 100 g.