Three ounces, three answers
English kept three different ounces, and they survive in different corners of life. The one you meet in kitchens, on bathroom scales and in post offices is the avoirdupois ounce: exactly 28.349523125 g, usually rounded to 28.35 g. Jewellers and bullion dealers use the troy ounce of 31.1034768 g. And the fluid ounce is a volume — 29.5735 ml in the US, 28.4131 ml in the UK — which only becomes a weight once you know the density of what you are pouring.
| Ounce | In grams | Used for |
|---|---|---|
| Avoirdupois ounce | 28.3495 g | Food, body weight, parcels |
| Troy ounce | 31.1035 g | Gold, silver, gemstones |
| Fluid ounce (US) | ≈ 29.57 g of water | Liquids by volume |
| Fluid ounce (imperial) | ≈ 28.41 g of water | Liquids by volume (UK) |
The troy trap
A troy pound has only 12 troy ounces, against 16 avoirdupois ounces in an everyday pound — yet each troy ounce is heavier. That is why a “pound” of gold weighs less than a pound of flour in grams (373.24 g against 453.59 g), and why comparing a gold price per ounce with a grocery price per ounce is meaningless without checking which ounce each side uses.
A quick conversion table
| Ounces | Grams | Kilograms |
|---|---|---|
| 1 oz | 28.35 g | 0.028 kg |
| 2 oz | 56.70 g | 0.057 kg |
| 4 oz | 113.40 g | 0.113 kg |
| 8 oz | 226.80 g | 0.227 kg |
| 16 oz (1 lb) | 453.59 g | 0.454 kg |
Why the exact figure matters less than the scale
In the kitchen, 28.35 g per ounce is precise enough — the difference between 28.35 and 28.3495 is invisible on any home scale. What actually changes results is weighing at all: a recipe that says “4 oz of flour” means about 113 g whether you scoop or spoon, while the same flour measured as “1 cup” can swing between 120 g and 150 g depending on technique. The ounces to grams converter handles any figure, and the flour measuring guide shows why weighing beats scooping for dry ingredients.
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