⚖️ Grams to Ounces Converter
Convert grams to ounces and back. The exact factor, a table of the values people look up most, and what each unit is actually used for.
Converting grams to ounces
One gram is 0.03527396195 ounces, and one ounce is 28.34952313 grams.
ounces = grams × 0.03527396195
Getting the precision right
1 ounce is exactly 28.349523125 grams, so 1 g is 0.0352739619 oz. In recipes, 25 g is routinely written as 1 oz even though the true figure is 0.88 oz — British cookbooks adopted 25 g as a convenient round substitute during metrication. For baking that 12% difference matters in small quantities and rarely matters in large ones.
Where each unit is used
Grams are standard for cooking and nutrition nearly everywhere. Ounces persist in American recipes and in British baking books written before the 1990s, which is why converting an old recipe is the most common reason anyone needs this.
Values worth knowing
| g | oz |
|---|---|
| 10 | 0.35274 |
| 25 | 0.881849 |
| 50 | 1.7637 |
| 100 | 3.5274 |
| 125 | 4.40925 |
| 200 | 7.05479 |
| 250 | 8.81849 |
| 400 | 14.1096 |
| 500 | 17.637 |
| 1000 | 35.274 |
100 g is 3.53 oz. A standard tin of tomatoes at 400 g is 14.1 oz. An ounce of chocolate is 28 g, about four squares of a standard bar.
Where the two units came from
The gram was defined in revolutionary France as the mass of a cubic centimetre of water at melting point, which is why a litre of water still weighs almost exactly a kilogram. The ounce descends from the Roman uncia, one twelfth of a libra — the same root that gives English the word inch, also originally a twelfth. The avoirdupois ounce used for food is one sixteenth of a pound, while the troy ounce used for gold is one twelfth of a troy pound and about 10% heavier.
Round the result to the precision your own work needs. These converters carry the full factor, which is useful for checking but rarely what you want to write down.
This rarely sits on its own: the kg to lbs picks up where it stops, and the lbs to stone answers the version of the question people ask next.
Frequently Asked Questions (FAQs)
How many grams are in an ounce?
Exactly 28.349523125 grams for the avoirdupois ounce used for food. Recipes usually round it to 28 g, and older British books use 25 g as a deliberate approximation.
Is a fluid ounce the same as an ounce?
No, and confusing them ruins recipes. An ounce measures weight; a fluid ounce measures volume. They coincide only for water, and even then only approximately, since a US fluid ounce of water weighs about 1.04 oz.
Why do old recipes say 25 g for 1 oz?
It was the official rounding used during British metrication, chosen because it keeps the proportions between ingredients consistent. Every quantity shrinks by the same 12%, so the recipe still works — it simply makes slightly less.