Last updated: September 2026
Weight conversion
Ounces to Grams
Convert food portions, recipes, mail weights, and small packaged goods from ounces to grams.
1 oz
28.349523125 g
g = oz × 28.349523125
The formula
How to convert ounces to grams
Apply g = oz × 28.349523125. For example, 1 oz equals 28.349523125 g.
Precision
Accurate constants, readable results
OmniUnit calculates with the full stored conversion factor, then displays up to 12 significant digits.
Common ounces conversions
| Ounces | Grams |
|---|---|
| 1 oz | 28.349523125 g |
| 2 oz | 56.69904625 g |
| 4 oz | 113.3980925 g |
| 8 oz | 226.796185 g |
| 12 oz | 340.1942775 g |
| 16 oz | 453.59237 g |
Related weight conversions
Frequently asked questions
How many grams are in 1 ounce?
One ounce equals 28.349523125 grams. The avoirdupois ounce is defined as exactly 1/16 of a pound, and the pound is defined as 0.45359237 kilograms, so 1 oz = 28.349523125 g is a fixed definition, not a measurement.
How many ounces are in 1 gram?
One gram equals 0.0352739619496 ounces. To convert grams back to ounces, use the grams-to-ounces page, which shows the exact formula and a quick calculator.
How do I convert ounces to grams without a calculator?
Multiply the ounces by 28.35 for a quick estimate — for example, 8 ounces is about 226.8 grams. For precise results, use the calculator above or multiply by 28.349523125.
Is the ounce-to-gram conversion exact?
Yes. The ounce is defined as exactly 1/16 of a pound and the pound as exactly 0.45359237 kilograms, so 1 oz = 28.349523125 g is a fixed definition, not an approximation.