Free ounces to grams calculator
Enter a weight in ounces — this ounces to grams converter applies the exact NIST factor (1 oz = 28.3495 g) instantly, updated live, as you type.
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Volume-to-weight conversions are approximate and vary by ingredient brand, moisture, and packing method.
Results are estimates. Consult a professional.
How the ounces to grams converter works
All cooking ounces are avoirdupois ounces — the everyday weight unit used in the US and UK for food, groceries, and kitchen scales. The conversion to grams is a single fixed multiplication: one avoirdupois ounce equals exactly 28.3495 grams. There is a second type of ounce — the troy ounce, equal to 31.1035 g — but it is used exclusively for precious metals and never appears in a recipe.
US recipes commonly specify produce, meat, cheese, and chocolate in ounces; European and professional recipes use grams. When scaling US recipes for a metric kitchen — or entering a weight from a US-labeled package into a metric recipe app — this conversion is the single step needed.
Worked example: converting a chocolate portion
Sofía is making a chocolate ganache and her French recipe calls for 170 g of dark chocolate, but the chocolate bars in her US grocery store are labelled in ounces. She needs to know how many ounces of chocolate to buy or snap off.
Ounces to grams — common cooking weights
The table covers the ounce weights you will most commonly encounter: produce portions, chocolate bars, cheese wedges, meat servings, and full-pound increments.
| Ounces | Grams | Kitchen context |
|---|---|---|
| ½ oz | 14.17 g | 1 tbsp butter; small spice portion |
| 1 oz | 28.35 g | Single shot; 2 tbsp cream cheese |
| 2 oz | 56.70 g | Small snack portion; ¼ cup nuts |
| 3 oz | 85.05 g | Standard single meat serving |
| 4 oz | 113.40 g | Quarter-pound; small chocolate bar |
| 6 oz | 170.10 g | Standard steak; Greek yogurt pot |
| 8 oz | 226.80 g | Half-pound; 1 cup shredded cheese |
| 12 oz | 340.19 g | ¾ lb; large can of tuna |
| 16 oz | 453.59 g | 1 lb; standard US bag of flour |
Source: NIST SP 811. 1 avoirdupois oz = 28.349523125 g exactly. Kitchen context notes are approximate; actual measures vary by density and brand.
Tips for converting ounces to grams in the kitchen
Once you know the single factor — 28.35 g per ounce — the arithmetic is trivial, but a few practical points make the conversion smoother when you are mid-recipe.
- Memorise 28 g per oz as your quick-estimate anchor — the true factor is 28.3495 g/oz, but 28 g/oz gives you a 1.2% underestimate that is close enough for shopping and rough scaling. For baking, always use the precise figure.
- Toggle your kitchen scale between oz and g — most digital kitchen scales switch units with one button press. If your scale shows oz and your recipe needs grams, toggle rather than convert manually; it removes all intermediate rounding.
- US package weights are in avoirdupois oz — a 12 oz can of tomatoes, an 8 oz block of cheese, a 16 oz box of pasta are all avoirdupois ounces, so the ×28.3495 factor applies directly.
- Do not confuse oz weight with fl oz — an 8 fl oz measuring cup holds 8 fluid ounces of volume, not 8 weight ounces. The weight of the contents depends on density. Only when the contents is water do 8 fl oz ≈ 236.6 g.
- Troy ounces never appear in food — if you ever see 'troy oz' on a scale display or label, switch to a standard mode. Troy ounces (31.1035 g) exist only for precious metals and are not a cooking unit.
Accuracy and limitations
The conversion factor 28.349523125 g per avoirdupois ounce is exact — it follows directly from the defined pound (453.59237 g) divided by 16. The calculator applies this factor with full floating-point precision, so any rounding visible in the result is a display artefact in the last decimal place, not a computational error.
The practical accuracy ceiling is set by your measuring equipment. A standard kitchen scale accurate to ±1 g introduces an error of about ±3.5% on a 1 oz measurement and less than ±0.5% on an 8 oz measurement. For baking, where ingredient ratios matter, use a scale with 0.1 g resolution for quantities under 10 g. This converter applies only to weight (mass) ounces — see the ounces to mL converter for fluid ounces.
Weight and ounce terms defined
About this ounces to grams converter
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