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Ounces to grams converter

Multiply ounces by 28.3495 to get grams. One avoirdupois ounce equals exactly 28.349523125 grams. This page covers weight ounces (oz), not fluid ounces (fl oz), which measure volume. The converter above uses the precise value for every result.

Ounces to grams quick reference

For other values, type them into the converter or multiply by 28.3495.

How to convert ounces to grams

The formula

grams = ounces x 28.3495

For rough estimates, multiply by 28. That is off by about 1.2%, which is close enough when you are eyeballing ingredients but not precise enough for medication or lab work.

Example 1: baking

A recipe calls for 6 oz of chocolate chips. 6 x 28.3495 = 170.1 g. A standard European baking bar is 200 g, so you would use about 85% of the bar.

Example 2: postage

A USPS First-Class letter can weigh up to 3.5 oz. 3.5 x 28.3495 = 99.2 g. If your kitchen scale reads grams, that is your cutoff before postage goes up.

Example 3: protein serving

A nutrition label says a serving of chicken breast is 4 oz. 4 x 28.3495 = 113.4 g. Most food scales sold outside the US display grams, so knowing this conversion helps portion meals accurately.

Example 4: jewelry

A silver bracelet weighs 1.5 oz. 1.5 x 28.3495 = 42.5 g. Precious metal pricing is sometimes quoted per gram or per troy ounce (31.1 g), so knowing the weight in grams helps compare prices across different markets.

When you need this conversion

Cooking and baking

American recipes measure dry ingredients in ounces and cups. European, Australian, and most international recipes use grams. A recipe calling for 8 oz of flour means 227 g. In baking, where ratios control texture, a 10% error from sloppy conversion can make bread too dense or cookies too flat.

Shipping small packages

USPS prices letters and small packages by the ounce. International carriers use grams or kilograms on customs forms. A 12 oz package is 340 g (0.34 kg). Writing the wrong weight on a customs declaration can hold up delivery or trigger additional inspection.

Nutrition and supplements

US nutrition labels list serving sizes in ounces. Imported supplements and international fitness programs use grams. A 2 oz protein bar is about 57 g. Tracking macros across products from different countries requires converting between the two.

Small-scale manufacturing

Soap making, candle making, and cosmetics often list ingredients in ounces in US guides and grams in international ones. Precision matters because fragrance oils, lye, and wax ratios affect both safety and quality. A 0.5 oz measurement error on fragrance oil (about 14 g) can make a batch of soap irritating to skin.

Common items by ounce and gram weight

Tips for accurate conversions

• Do not confuse ounces (oz) with fluid ounces (fl oz). Ounces measure weight. Fluid ounces measure volume. 8 fl oz of water weighs about 8.3 oz, but 8 fl oz of honey weighs about 11.3 oz because honey is denser.
• Troy ounces, used for gold and silver, are different from regular ounces. One troy ounce is 31.1035 g, about 10% heavier than a standard ounce (28.3495 g).
• For baking, weigh ingredients rather than using volume measures. A cup of flour can vary from 120 g to 160 g depending on how tightly it is packed. Weight measurements eliminate that variation.
• Most digital kitchen scales toggle betweenounces and grams. If yours does, switch to grams when following international recipes rather than converting manually.

Ounces, troy ounces, and fluid ounces

The avoirdupois ounce (28.3495 g) is the standard ounce used in grocery stores, kitchens, and shipping. There are 16 of them in a pound. The troy ounce (31.1035 g) is used exclusively for precious metals and gemstones. There are 12 troy ounces in a troy pound, which makes a troy pound lighter than a regular pound despite each individual troy ounce being heavier.

Fluid ounces measure volume, not weight. In the US system, 1 fluid ounce = 29.5735 mL. In the UK imperial system, 1 fluid ounce = 28.4131 mL. The US and UK fluid ounce are not interchangeable, which occasionally causes confusion with imported recipes.

Frequently asked questions

How many grams is 1 ounce?

1 oz = 28.3495 grams.

How many ounces is 100 grams?

100 g = 3.527 oz. Divide grams by 28.3495 to convert to ounces.

How many grams is 8 ounces?

8 oz = 226.8 g. That is half a pound.

Is an ounce exactly 28 grams?

No. An ounce is 28.3495 grams. Using 28 as a shortcut undershoots by about 1.2%, which adds up when measuring several ounces.

How do I convert grams back to ounces?

Divide grams by 28.3495, or multiply by 0.035274. For example, 250 g / 28.3495 = 8.82 oz.

What is the difference between oz and fl oz?

Oz measures weight. Fl oz measures volume. They are not interchangeable. The weight of a fluid ounce depends on the density of the liquid.

How many grams in a pound?

1 pound = 453.592 grams. That is 16 ounces, each at 28.3495 g.

Why do gold prices use a different ounce?

Gold and other precious metals use the troy ounce (31.1035 g), which predates the avoirdupois ounce and comes from the medieval trading system based in Troyes, France. The troy system stuck for precious metals because it was already the established standard when the avoirdupois system was adopted for general commerce.

Related conversion tools

• Weight Converter
• Pounds to Kilograms Converter
• Inches to Centimeters Converter
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Measurement guides

• How Big Is X Inches? A Visual Size Guide From 1 to 16 Inches
• Inches Explained: Conversion Chart, Tools, and Real-World Examples

Formula & Explanation

The avoirdupois ounce is defined as exactly 28.349523125 grams. This is the ounce used for most everyday weighing in the US. (A troy ounce, used for precious metals, is 31.1034768 g — a different unit.)