How many grams are in one ounce?

Exactly 28.349523125 grams. This is the internationally defined NIST value for the avoirdupois ounce, which is the standard ounce used in everyday commerce, cooking, and postal weighing in the US and UK.

Is this the avoirdupois ounce or the troy ounce?

This tool converts avoirdupois ounces (oz av), the everyday unit used for food, parcels, and body weight. The troy ounce (oz t) used for precious metals is heavier: 1 troy ounce = 31.1034768 grams. If you are weighing gold or silver, use a troy-ounce converter instead.

How do I convert 100 grams to ounces?

Divide by 28.349523125: 100 ÷ 28.349523125 = 3.527396 oz. The calculator does this automatically — just type 100 in the grams field.

How accurate is the conversion?

The factor used (28.349523125 g/oz) is the exact NIST-defined value, so the only rounding occurs in the displayed decimal places. Results are shown to up to 6 significant decimal places, which is more than sufficient for cooking, shipping, or laboratory use.

Can I convert ounces back to grams?

Yes. The converter is fully bidirectional. Type a value in the ounces field and grams updates instantly. The reverse formula is g = oz × 28.349523125.

What is 1 gram in ounces?

1 gram = 0.035274 ounces (rounded to 6 decimal places). In practical terms, 1 gram is about the weight of a paperclip or a small sugar packet — far less than a single ounce.

Grams to Ounces Converter

Converting between grams and ounces is one of the most common weight-conversion tasks in everyday life. Recipes sourced from the United States list ingredients in ounces, while European and international recipes stick to grams. Postal services, supplement labels, and jewellery listings switch between the two constantly. This tool removes the friction: type a value in either field and the other updates in real time.

The exact conversion factor

The avoirdupois ounce is defined as 28.349523125 grams — an exact value fixed by international agreement (NIST Special Publication 330). There is no rounding involved in the definition itself, so any imprecision in a result comes only from the number of decimal places displayed, not from the underlying formula.

The two conversion formulas are:

oz = g ÷ 28.349523125

g = oz × 28.349523125

Avoirdupois vs troy ounce

This calculator uses the avoirdupois ounce — the everyday ounce stamped on food packaging, used by postal scales, and cited in US customary recipes. It is not the same as the troy ounce (31.1034768 g), which is reserved for precious metals such as gold and silver. If you are converting bullion weights, you need a separate troy-ounce tool.

Worked example

A US recipe calls for 6 oz of dark chocolate. To find the gram equivalent:

6 × 28.349523125 = 170.097 g

Rounding to the nearest gram gives 170 g — a standard quantity easily weighed on a kitchen scale. Going the other way, if your scale reads 250 g of flour and you need to report it in ounces for a US audience:

250 ÷ 28.349523125 = 8.818 oz

Common reference conversions

Grams	Ounces
1 g	0.035274 oz
28.35 g	≈ 1 oz
100 g	3.527396 oz
250 g	8.818490 oz
500 g	17.636981 oz
1000 g	35.273962 oz

One ounce is very close to 28.35 g, so a quick mental approximation is to divide grams by 28 for a rough ounce figure — but use this tool when accuracy matters.

Why the factor has so many decimal places

The gram and the ounce belong to different measurement systems — the metric SI system and the US/UK customary system respectively. Their ratio is an irrational-looking decimal because the two systems were defined independently. The NIST value (28.349523125) is the exact legal definition adopted by the international yard and pound agreement of 1959, and it has not changed since.

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