Grams to Ounces Converter & Formula

This calculator converts a weight in grams to ounces (avoirdupois) and shows the result instantly. Enter any number of grams, and you get the equivalent in ounces, plus the reverse conversion if you need it. The formula is simple: 1 ounce equals 28.349523125 grams exactly.

Formula

The conversion between grams and ounces uses a fixed international standard. The exact relationship is:

ounces = grams ÷ 28.349523125

Where:

• grams – the mass you start with, in grams (g)
• ounces – the result, in avoirdupois ounces (oz)
• 28.349523125 – the exact number of grams in one ounce, defined by international agreement in 1959

For everyday cooking and weighing, most people round this to 28.35 grams per ounce. For nutrition labels, the US Food and Drug Administration uses 28.35 g/oz for labeling, which is slightly rounded from the exact value.

Worked Example

Using the default value of 100 grams from the calculator:

1. Start with 100 grams.
2. Divide by 28.349523125: 100 ÷ 28.349523125 = 3.527396195
3. Round to 4 decimal places: 3.5274 ounces

So 100 grams is approximately 3.53 ounces. For a quick mental check, remember that 28 grams is about 1 ounce, so 100 grams is a bit more than 3.5 ounces – that matches.

Why Two Different Units?

Grams and ounces come from two different measurement systems. Grams are the base unit of mass in the metric system (SI), used almost everywhere in the world for science, cooking, and daily life. Ounces are part of the imperial and US customary systems, still common in the United States and a few other countries for food, postal mail, and body weight.

The avoirdupois ounce (the one used for everyday weights) is 1/16 of a pound. There are also troy ounces used for precious metals (31.1034768 g), but those are not what this calculator uses. Unless you are buying gold or silver, always assume avoirdupois ounces.

How to Use the Calculator

Type any positive number into the grams field. The calculator immediately shows:

• Ounces – the main result, rounded to 4 decimal places.
• Grams per ounce – the conversion factor, shown for reference.

You can enter decimals (e.g., 250.5 g) or very large numbers. The minimum is 0 grams – negative weights don’t make sense for mass. The result updates as you type, so you don’t need to press a button.

Common Mistakes and How to Avoid Them

• Using the wrong ounce: Remember that troy ounces (for metals) are different. This calculator uses standard avoirdupois ounces.
• Rounding too early: If you round 28.3495 to 28 before dividing, your answer will be off by about 1.2%. For most cooking, that’s fine; for precise chemistry, it’s not.
• Confusing fluid ounces: Fluid ounces measure volume, not weight. 1 fluid ounce of water weighs about 1.043 ounces, but for other liquids it varies. This calculator only converts mass (grams to ounces).
• Reversing the operation: To convert ounces to grams, multiply by 28.3495, not divide. A common error is dividing when you should multiply.

Practical Uses for This Conversion

You’ll need this conversion in many real situations:

• Cooking and baking: Many European recipes list ingredients in grams, while American recipes use ounces. A kitchen scale that shows both is handy, but this calculator works when you only have one unit.
• Nutrition and diet: Food labels in the US show serving sizes in grams, but you might think in ounces. For example, a 56 g serving of cereal is about 2 ounces.
• Shipping and postage: Postal rates often depend on weight in ounces, but you might weigh your package on a metric scale.
• Science and education: Lab work often requires converting between metric and imperial units for reports or experiments.
• Jewelry and crafts: Beads, wire, and small parts are often sold in grams, but project instructions may call for ounces.

Quick Reference: Common Gram-to-Ounce Conversions

Here are some frequently used values (rounded to 2 decimal places):

• 1 g = 0.04 oz
• 10 g = 0.35 oz
• 28.35 g = 1 oz
• 50 g = 1.76 oz
• 100 g = 3.53 oz
• 250 g = 8.82 oz
• 500 g = 17.64 oz
• 1000 g (1 kg) = 35.27 oz

For a rough mental estimate, divide grams by 28. For more precision, use the exact factor 28.3495.

Frequently Asked Questions

How many grams are in an ounce?

Exactly 28.349523125 grams. Most recipes and nutrition labels round to 28.35 grams per ounce. If you’re converting a recipe, using 28.35 is accurate enough for cooking.

Is 100 grams the same as 3.5 ounces?

Yes, almost. 100 g ÷ 28.3495 = 3.5274 oz, which rounds to 3.5 ounces. For most practical purposes, 100 g ≈ 3.5 oz is a good approximation.

How do I convert ounces to grams?

Multiply the number of ounces by 28.349523125. For example, 8 oz × 28.3495 = 226.796 g. Many people round to 28.35, so 8 oz ≈ 226.8 g.

Why do some scales show both grams and ounces?

Because both units are widely used. Digital kitchen scales often have a button to switch between metric and imperial. This calculator serves the same purpose for when you don’t have a scale or need a quick conversion.

What is the difference between a fluid ounce and an ounce?

A fluid ounce (fl oz) measures volume, while an ounce (oz) measures mass or weight. One fluid ounce of water weighs about 1.043 ounces, but for oil, honey, or other liquids, the weight differs. This calculator only converts grams (mass) to ounces (mass), not to fluid ounces.

Is the ounce used in the UK the same as the US ounce?

Yes, for everyday weights, the avoirdupois ounce is identical in both countries. The UK also uses the metric system for most trade, but the imperial ounce is the same 28.3495 g. The only difference is that the UK uses the term “ounce� for both mass and sometimes volume (fluid ounce), which is a separate unit.

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in g | Grams | g | 100 | 0
out oz | Ounces | oz | g / 28.349523125 | 4
out g_rev | Grams per ounce | g/oz | 28.349523125 | 4