Convert ounce to gram.

About this conversion

Ounces-to-grams: multiply by 28.3495. Used in cooking, jewelry/metals, mailing, and small product weights.

Formula

g = oz × 28.3495

Real-world examples

Reference values

Tips & tricks

• There are three "ounces": avoirdupois (everyday), troy (precious metals), and fluid ounce (volume). The first two are mass; the third isn't. Don't confuse.
• Coffee dosing is often in grams (18g for a double espresso). Knowing the gram weight of a "scoop" or "tablespoon" of beans is important for consistency.
• Postal weights internationally are in grams; US postal weights are in ounces — for international shipping prep, convert.

Origin & history

The avoirdupois ounce (the everyday US ounce, 1/16 of a pound) is 28.3495 g. The troy ounce (used for precious metals) is heavier: 31.1035 g. Always check which you're working with.

What is a ounce?

One avoirdupois ounce equals exactly 28.349523125 grams or one-sixteenth of a pound. US food packaging, postal weights, and recipes.

What is a gram?

The gram is the metric unit of mass equal to one-thousandth of a kilogram. Food portions, ingredients, postage, and small-object weights.

How big is one oz in real terms?

It's often easier to understand a unit when paired with familiar examples. 1 oz is about the weight of a slice of bread; 8 oz is about a cup of water; and 16 oz is one pound — about the weight of a deck of cards three times over.

How to convert ounce to gram

To convert a value from ounce (oz) to gram (g), apply the conversion factor shown in the formula above. The calculation is the same whether you do it by hand, in a spreadsheet, or with the live converter on this page.

Steps:

1. Take your input value in oz.
2. Apply the formula see formula above.
3. The result is your value in g.

For repeated calculations, save the formula in a spreadsheet or use the live converter at the top of this page — it handles the math automatically and displays the result as you type.

Frequently asked questions

How do I convert oz to g?

Apply the formula oz → g shown above, or just type your value into the converter at the top of this page. The result updates instantly.

Which is bigger, oz or g?

This depends on the conversion ratio in the formula. If the factor multiplied by your value gives a larger number, then g is the smaller unit (so it takes more of them to express the same quantity). If the result is smaller, then g is the larger unit.

When would I use oz versus g?

Both units measure mass, so the choice depends on context. Ounce is typically used for shipping, scientific measurement, cooking, and commerce; gram similarly. Most professional fields standardize on one or the other based on regional conventions or technical tradition.

How precise is this oz to g conversion?

The conversion factor shown is the internationally defined exact value (or the best-published approximation if the relationship is irrational, like degrees-to-radians). The live converter on this page uses double-precision floating-point math, accurate to about 15 significant digits — far beyond any practical engineering need.

Is the conversion ratio exact, or an approximation?

Most unit conversions between SI metric units, and between SI and US customary units, have been formally defined as exact values since the 1959 international yard-pound agreement and subsequent SI redefinitions. Exceptions are unit pairs that involve irrational numbers (radians, e.g.) or empirical conversions (like food calories, which depend on temperature). When in doubt, consult the formula at the top of this page.

Related conversions

See also