How this works
1 ounce = 28.3495 grams (the avoirdupois ounce: 1 lb / 16 = 0.45359237 / 16 kg, expressed in grams). Useful for cooking when a US recipe gives ingredients in ounces and you need grams for a kitchen scale, for postage from a metric country, or for craft and jewellery measurements.
The formula
For mental conversion, multiply oz by 28 — within 1.6%. So 8 oz × 28 ≈ 224 g (actual 226.8). Note: this calculator uses the avoirdupois ounce (the standard "weight" ounce). The troy ounce, used for precious metals, is heavier — 31.1035 g — and is not what the calculator returns.
Example calculation
- 1 oz = 28.35 g
- 4 oz = 113.4 g (≈ a stick of US butter)
- 8 oz = 226.8 g (½ lb)
- 16 oz = 453.6 g (1 lb)
Frequently asked questions
Is "oz" the same as a fluid ounce?
No — those are different units that share an abbreviation. Weight ounce (oz) measures mass: 28.3495 g. Fluid ounce (fl oz) measures volume: ≈ 29.57 mL (US) or 28.41 mL (UK). For water and similar-density liquids the numbers happen to be close, which is why the confusion is common, but they're not interchangeable for other substances. This calculator handles the weight ounce only.
How many grams in a cup of flour?
Volume → mass conversions depend on the substance. A US cup is ~240 mL, but the mass it holds varies: all-purpose flour ≈ 125 g, granulated sugar ≈ 200 g, water ≈ 240 g. This calculator only converts oz (mass) to g (mass) — for cup-to-gram conversions you need a recipe-specific lookup since density differs by ingredient.