Ounces to Grams
Convert ounces to grams instantly. Free, fast, no signup.
How to use this tool
- Enter ounces in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your grams and the full breakdown beneath it.
Convert ounces to grams instantly. Free, fast, no signup.
Formula
Grams = Ounces × 28.349523125
One avoirdupois ounce equals exactly 28.349523125 grams, derived from 0.45359237 kg ÷ 16.
How it works
Multiply the number of avoirdupois ounces by 28.349523125 to obtain grams. This factor is exact (derived entirely from the defined pound and the defined number of ounces per pound), so any decimal in the result comes only from the input value, not from rounding the factor.
Common mistake: A popular shortcut is to multiply ounces by 28 or 30, both of which are wrong in different directions. Using 28 underestimates by about 1.2%; using 30 overestimates by about 5.8% — the latter is common in informal cooking conversions but can matter in pharmaceutical or laboratory settings.
Worked example
Convert 1 ounce to grams
- Start with 1 ounce.
- Multiply by the exact factor: 1 × 28.349523125.
- Round to four decimal places: 28.3495 g.
1 ounce = 28.3495 grams
Common mistakes to avoid
- Confusing avoirdupois ounces (28.3495 g) with troy ounces (31.1035 g) -- using this converter for gold or silver will understate the gram weight by about 9.8%.
- Using 28 as an approximation instead of 28.3495, understating each ounce by 0.35 g -- accumulates noticeably over several ounces in baking.
- Multiplying by 0.03527 instead of 28.3495 -- that converts grams to ounces.
Key terms
- Avoirdupois ounce (oz)
- A unit of mass equal to 1/16 of an avoirdupois pound, or exactly 28.349523125 grams.
- Gram (g)
- The metric unit of mass equal to 1/1000 of a kilogram; widely used in food labeling and science.
- Exact factor
- A conversion multiplier derived from defined (not measured) values, meaning it introduces no rounding uncertainty of its own.
- Fluid ounce vs. weight ounce
- Fluid ounces (fl oz) measure volume, not mass; they are not interchangeable with weight ounces (oz) even for water (1 US fl oz of water ≈ 29.57 g, not 28.35 g).
Frequently asked questions
- How do I convert ounces to grams?
- Multiply the number of ounces by 28.3495 to get grams.