Ounces vs Grams
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
US recipes, US/UK grocery weights, postage. Boxing and MMA glove weights.
All European recipes, scientific work, pharmaceuticals (mg/g matter for dosing), most non-US grocery labels.
| Aspect | Ounces | Grams |
|---|---|---|
| Type | Avoirdupois (everyday) or Troy (precious metals) | Single SI definition |
| 1 unit equals | 28.3495 g (avoirdupois) | 0.0353 oz |
| Precision needed | Acceptable for cooking | Required for pharma and science |
| UK recipes | Common in older recipes (pre-1980) | Standard in modern UK recipes |
Frequently asked
Is a troy ounce the same as a regular ounce?
No. A troy ounce (31.1035 g) is about 10% heavier than the regular avoirdupois ounce (28.3495 g). Gold and silver are sold by troy ounces — 1 oz of gold means 31.1 g, not 28.3 g.
How many grams in 8 oz?
8 oz (avoirdupois weight) = 226.8 g, often rounded to 225 g in UK recipes. Note: 8 fl oz (fluid ounces) ≠ 8 oz by weight. 1 oz weight = 28.35 g. This distinction is critical — weight oz and fluid oz are different units entirely.
Frequently asked questions
Is a troy ounce the same as a regular ounce?
No. A troy ounce (31.1035 g) is about 10% heavier than the regular avoirdupois ounce (28.3495 g). Gold and silver are sold by troy ounces — 1 oz of gold means 31.1 g, not 28.3 g.
How many grams in 8 oz?
8 oz (avoirdupois weight) = 226.8 g, often rounded to 225 g in UK recipes. Note: 8 fl oz (fluid ounces) ≠ 8 oz by weight. 1 oz weight = 28.35 g. This distinction is critical — weight oz and fluid oz are different units entirely.