The gram (metric) and the avoirdupois ounce (US customary) both have exact definitions, making this a precise weight conversion.
How it works
Dividing grams by 28.349523125 gives ounces; multiplying ounces by that same constant gives grams back. Type into either field and the other updates instantly.
What this does not include
This does not include the troy ounce, a different (heavier) ounce used for precious metals like gold and silver — this calculator uses the standard avoirdupois ounce for everyday weight.
How to use this calculator
- Enter a value in either grams or ounces — the other field fills in automatically.
Frequently asked questions
Why is 16 ounces exactly 453.59237 grams?
Because 16 ounces equals exactly 1 avoirdupois pound, and the international pound was defined in 1959 as exactly 453.59237 grams — the ounce conversion follows directly from that.
Is a troy ounce the same as this?
No — a troy ounce (used for gold, silver, and other precious metals) is about 10% heavier than the avoirdupois ounce this calculator converts.
Where is this conversion most commonly needed?
Cooking (many international recipes use grams, many US recipes use ounces), postal/shipping weight, and reading nutrition labels from different countries.
