This calculator converts grams to ounces, and ounces back to grams, using the exact international conversion factor of 1 oz = 28.349523125 g. Grams are the standard metric unit for weighing small amounts, from food and spices to jewellery and postage, while ounces are still widely used in recipes, gym equipment, and precious metal pricing, so having an accurate way to move between the two saves you from rounding errors and guesswork. Enter a weight in grams, or type a figure straight into the ounces field to convert the other way, and choose whether you want avoirdupois ounces (the everyday standard used for food and general goods) or troy ounces (used for gold, silver, and other precious metals, and about 9.7% heavier). The calculator instantly returns the result in ounces, the equivalent in grams, a pounds-and-ounces breakdown for reference, and the underlying conversion factor, along with a quick reference table covering common weights from one ounce up to a kilogram. Nine preset buttons let you jump straight to typical NZ pack sizes like 125 g butter blocks, 250 g, 500 g, and 1 kg without typing. Because avoirdupois and troy ounces differ, always check which type you need, especially when weighing precious metals.
You can also type ounces here to convert back to grams.
Click a common quantity to fill it in.
| Grams (g) | Avoirdupois oz | Troy oz | Pounds + oz |
|---|
The avoirdupois ounce is the standard ounce used in everyday life for food, postage, and general goods. The international standard defines 1 pound (lb) as exactly 453.59237 grams. Since there are 16 ounces in a pound, 1 oz = 453.59237 / 16 = 28.349523125 g exactly.
To convert grams to ounces, divide by 28.349523125:
Ounces = Grams / 28.349523125
To go the other way (ounces to grams), multiply by 28.349523125:
Grams = Ounces x 28.349523125
Convert 100 grams to ounces:
This matches the default output shown in the calculator above.
There are two ounce systems in common use:
| Ounce type | Grams | Common uses |
|---|---|---|
| Avoirdupois oz (oz av) | 28.349523125 g | Food, postage, general goods, body weight in some countries |
| Troy oz (oz t) | 31.1034768 g | Gold, silver, platinum, gemstones |
The troy ounce is about 9.7% heavier than the avoirdupois ounce. If you are converting precious metal weights, use the troy option in this calculator.
| Grams | Avoirdupois oz | Context |
|---|---|---|
| 28.35 g | 1.000 oz | One ounce of food or spice |
| 100 g | 3.527 oz | Typical serving or small pack |
| 125 g | 4.409 oz | Common NZ butter block size |
| 250 g | 8.818 oz | Half-pound equivalent |
| 454 g | 16.014 oz | 1 lb (approximately) |
| 500 g | 17.637 oz | Standard half-kilogram pack |
| 1,000 g | 35.274 oz | 1 kilogram |
Sources and method: International Bureau of Weights and Measures (BIPM): the avoirdupois pound is defined as exactly 453.59237 grams (NIST Handbook 44). Troy ounce: 1 troy pound = 12 troy oz = 373.2417216 g, giving 1 troy oz = 31.1034768 g (London Bullion Market Association, ISO 4217 XAU convention).
This calculator uses the international avoirdupois standard by default. For precious metal weights, select the troy ounce option. Results are rounded to four decimal places for display; the underlying computation uses full precision.
100 grams equals 3.5274 ounces (avoirdupois). The exact conversion factor is 1 oz = 28.349523125 g, so 100 g divided by 28.349523125 gives 3.52739619... oz, which rounds to 3.527 oz to three decimal places.
Avoirdupois ounces (oz av) are the standard ounce used for everyday goods, food, and postage. One avoirdupois ounce equals 28.349523125 grams. Troy ounces (oz t) are used for precious metals such as gold and silver. One troy ounce equals 31.1034768 grams, making it about 10% heavier than an avoirdupois ounce. This calculator uses avoirdupois ounces unless you select the troy option.
To convert ounces to grams, multiply the number of ounces by 28.349523125. For example, 5 oz x 28.349523125 = 141.748 g. This calculator includes a reverse field so you can enter ounces and read the grams result directly.
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