Convert grams to ounces and back for food packages, recipes, postage and portion sizes, with the result as a kitchen-friendly fraction, pounds and ounces for larger amounts, and a troy-ounce option for precious metals.
1 oz = 28.349523125 g · 1 g = 0.035274 oz
The ounce has been defined as exactly 28.349523125 grams since 1959, when the US and Commonwealth countries agreed on the international pound of 453.59237 g (an ounce is 1/16 of that). Divide grams by 28.35 for ounces, or multiply ounces by 28.35 for grams. Rounding to 28.35 is accurate to better than 0.002%, far finer than any kitchen scale.
For mental math, 30 g is close to 1 oz (6% high), so 100 g is roughly 3½ oz and 250 g roughly 9 oz.
Many US packages are sized in round ounces and labelled with rounded grams (12 oz = 340 g), while European ones use round grams. That's why a recipe from one side of the Atlantic rarely matches a pack on the other.
| Grams | Ounces | Nearest ⅛ oz | Typical item |
|---|---|---|---|
| 5 g | 0.18 | ⅛ | Teaspoon of sugar |
| 28 g | 0.99 | 1 | Single-serve bag of chips |
| 50 g | 1.76 | 1¾ | Chocolate bar |
| 85 g | 3 | 3 | Cooked meat serving (3 oz) |
| 100 g | 3.53 | 3½ | Nutrition labels outside the US |
| 113 g | 3.99 | 4 | Quarter-pound burger patty (raw) |
| 125 g | 4.41 | 4⅜ | European yogurt pot |
| 200 g | 7.05 | 7 | Chocolate bar, large |
| 227 g | 8.01 | 8 | Half-pound (8 oz) block of cheese |
| 250 g | 8.82 | 8⅞ | Standard butter or coffee pack, Europe |
| 340 g | 11.99 | 12 | 12 oz bag of coffee |
| 397 g | 14 | 14 | 14 oz can (beans, tomatoes) |
| 454 g | 16.01 | 16 | One pound |
| 500 g | 17.64 | 17⅝ | Pasta or flour pack, Europe |
US recipes, spice blends and craft supplies often give small weights as fractions of an ounce. In grams:
| Ounces | Grams |
|---|---|
| 1/16 oz | 1.77 |
| ⅛ oz | 3.54 |
| ¼ oz | 7.09 |
| ½ oz | 14.17 |
| ¾ oz | 21.26 |
| 1 oz | 28.35 |
A card with a small gift weighs 45 g on a kitchen scale. US First-Class Mail letters are priced per ounce, rounding up, and a letter can weigh at most 3.5 oz. What do you pay for?
Step 1: Grams to ounces
Step 2: Round up to the next whole ounce
Step 3: Check the letter limit
Anything from 28.4 g to 56.7 g pays the 2 oz rate. Over 99.2 g, or thicker than ¼ inch, it's charged as a large envelope (flat) instead. A rigid or lumpy item can also be charged extra, whatever it weighs.
US dietary advice is written in ounces. A standard cooked serving of meat, poultry or fish is 3 oz, about 85 g. USDA's MyPlate also uses "ounce-equivalents", which aren't always weights: 1 oz-equivalent of protein is 1 oz of meat, but also 1 egg, 1 tbsp of peanut butter or ½ oz of nuts. A recipe or plan that says "5½ oz-eq of protein a day" is counting servings, not grams.
Snack labels often show a 1 oz serving as "28 g". Weighing your portion in grams and dividing by 28.35 tells you how many label servings you actually ate.
Precious metals are priced per troy ounce, 31.1034768 g, about 10% heavier than the ordinary ounce. A "1 oz" gold coin weighs 31.1 g of gold, not 28.35 g. Choose the troy option above when converting bullion, coin or scrap-metal weights to match a spot price.
For gold jewellery, multiply by the purity too: 14 karat is 58.3% gold, so that ring holds about 0.19 oz t of pure gold.
An ounce (oz) is a weight; a fluid ounce (fl oz) is a volume of 29.57 mL in the US. They only line up for water, and even then not exactly: 100 g of water is 3.53 oz by weight but 3.38 US fl oz by volume. Grams can only be converted to ounces of weight. For liquids measured in fl oz, convert through millilitres and the liquid's density.
Most digital kitchen scales read in 1 g steps in metric mode but only 0.1 oz (2.8 g) or ⅛ oz (3.5 g) steps in ounce mode. For small amounts like yeast, salt or coffee, gram mode is about three times more precise, so it's worth switching even when a recipe is written in ounces. Convert the recipe once, then weigh in grams.
3.53 oz, or about 3½ oz.
113.4 g, a quarter of a pound. Packages often round it to 113 g.
Close but not exact. 1 oz is 28.35 g, so 30 g is 1.06 oz. Nutrition labels round a 1 oz serving to 28 g.
35.27 oz, which is 2 lb 3.27 oz.
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