Ounces to grams converter, kitchen ounces, troy ounces and fluid ounces.

To convert ounces to grams, multiply the ounces by 28.349523125. One ounce is 28.3495 g, 4 oz is 113.4 g and 16 oz is 453.59 g. This is the avoirdupois ounce, used for food, post and body weight. Three other things share the word: the troy ounce for gold, the fluid ounce for drinks and the label ounce of 28 g. The sections below keep them apart.

How to use the converter

1. Type the weight in the Ounces (oz) box, for example 8. Decimals and fractions such as 2 1/2 work.
2. The big result shows Grams (g). The cards show pounds and ounces, kilograms and pounds.
3. Type grams in the second box to go back to ounces, or open the Grams to ounces converter page.
4. Use Decimals: 0 or 1 for cooking, more for a jeweler. Click a row in Common values to load it.
5. Press Copy result, Copy link or Print chart.

The definition

The ounce is one sixteenth of the pound. NIST Handbook 44 (2026), Appendix C lists the pound as 453.592 37 grams exactly, so the ounce is exactly 28.349523125 g, a number that ends. Page checked 18 Oct 2026. In the same table the avoirdupois ounce is 437.5 grains exactly. That is how the troy ounce is told apart: the same appendix lists 1 ounce troy as 480 grains exactly and 1 grain as 64.798 91 milligrams exactly. So a troy ounce is 480 × 64.79891 mg, which is exactly 31.1034768 g.

Shortcuts and their errors

Multiply by 28 for a quick sum. That is 1.23 percent low: 8 oz gives 224 g against the exact 226.8 g. Multiply by 28.35 and you are within 0.0017 percent, so 8 oz gives 226.8 g. The US label rule is another figure again. 21 CFR 101.9(b)(5)(viii) says that for nutrition labelling 1 oz in weight means 28 g. A recipe or a pack that quotes 28 g for an ounce is rounded, so 16 oz comes to 448 g there, which is 5.6 g short of a true pound. For a postal rate or a gold price, use the exact figure.

Worked examples

• 4 oz of butter. 4 × 28.349523125 = 113.4 g.
• 8 oz of chocolate. 226.8 g.
• A 12 oz bag. 340.19 g. That is three quarters of a pound.
• 2 1/2 oz. Type 2 1/2. 70.874 g.
• 1 oz of gold. By troy that is 31.1035 g. By the kitchen ounce it would be 28.3495 g, a difference of 2.754 g.

Kitchen ounce against troy ounce

The troy ounce is 9.71 percent heavier than the ounce on a kitchen scale. The table puts the two side by side.

The troy pound has 12 ounces, so it weighs 373.242 g, less than the 16 ounce avoirdupois pound of 453.592 g. The names are alike and the weights are not. HB44 uses "ounce troy" or "oz t" for the troy ounce, and plain "ounce" for the kitchen one.

The mistake: a weight ounce is not a fluid ounce

8 oz on a scale is 226.8 g of food. 8 fl oz in a measuring cup is 236.6 mL of liquid. They are different kinds of unit, and a converter cannot change one into the other without the density of the food. A cup of one food weighs a different amount from a cup of another. If a recipe says "8 oz" next to a liquid, it most likely means fluid ounces, and the Oz to mL gives milliliters. If it says 8 oz next to flour, butter or chocolate, it means weight, and this page gives grams. When in doubt, a recipe that lists both, such as 8 oz (225 g), is giving you its own rounded conversion.

Pounds and ounces to grams

A weight written as 2 lb 4 oz is 36 oz in total. Turn the pounds into ounces first, add the rest, and convert once: 2 × 16 + 4 = 36 oz, and 36 × 28.349523125 = 1,020.58 g. The same answer comes from the other route, 2.25 lb × 453.59237 = 1,020.58 g. The cards show pounds and ounces for your amount so you can check one against the other. For a baby weight or a parcel see the Grams to pounds.

Check the answer, and how many decimals to keep

Divide the grams by 28.349523125 and you should have the ounces again: 226.796 g ÷ 28.349523125 = 8 oz. Grams are always the bigger number, about 28 times the ounces.

The right number of places depends on the job. A cake needs whole grams: 113 g for 4 oz. A letter or small parcel can use one decimal: 42.5 g for 1 1/2 oz. A coin or a piece of jewelry needs three or four places, and it needs the troy ounce, so check which ounce the seller uses. Set Decimals and the table will use the same number of places for every row.

Who uses ounces to grams

Cooks and bakers with a metric scale and a US recipe. Shoppers comparing a pack in ounces with one in grams. Senders of parcels where the rate is set in ounces. Coin and bullion buyers, who need the troy ounce. For the pounds side, the Ounces in a pound and the LBS to KG converter cover the rest.