How this calculator works
The avoirdupois ounce is exactly one sixteenth of the pound, which is exactly 0.45359237 kg, giving 28.349523125 g exactly. The conversion factor is exact; uncertainty in the original measurement still applies.
Formula
grams = ounces × 28.349523125.
Worked example
8 oz to grams: 8 × 28.349523125 = 226.796185 g, displayed as 226.796 g.
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Frequently asked questions
Is an ounce on a food label 28.35 g?
Labels round it. The legal factor is exactly 28.349523125 g, and this page uses the full definition rather than the rounded figure.
What about fluid ounces in a recipe?
Those measure volume, not mass. Use the millilitres to fluid ounces page for liquid amounts.
Can I convert a fraction of an ounce?
Yes. Decimal ounces multiply exactly, so 0.5 oz is 14.1747615625 g before display rounding.