Grams to Ounces Converter & Formula

This calculator converts a weight in grams to ounces (avoirdupois) instantly. Enter the number of grams, and you get the equivalent weight in ounces, plus the same value in pounds and ounces for convenience. The conversion uses the standard international factor: 1 ounce = 28.349523125 grams.

Formula

The conversion from grams to ounces is a simple division:

Ounces = Grams ÷ 28.349523125

Where:

• Grams (g) – the metric unit of mass you start with.
• Ounces (oz) – the avoirdupois ounce, the standard unit of weight in the US customary system.
• 28.349523125 – the exact number of grams in one avoirdupois ounce (defined by international agreement in 1959).

For everyday cooking, most people round this to 28.35 g per ounce or even 28 g per ounce. The calculator above uses the full exact value, so your result is precise to 3 decimal places.

Worked Example

Using the default value of 250 grams from the calculator:

1. Start with the formula: Ounces = Grams ÷ 28.349523125
2. Plug in 250: 250 ÷ 28.349523125
3. Calculate: 250 ÷ 28.349523125 = 8.818490487…
4. Round to 3 decimal places: 8.818 ounces

So 250 grams is approximately 8.82 ounces. The calculator also shows that this equals 0 pounds + 8.82 ounces (since 250 g is less than 1 pound, which is 453.592 g).

Why the Conversion Factor Is 28.349523125

The avoirdupois ounce (the one used for food, mail, and most everyday weights in the US) is defined as exactly 1/16 of a pound. The pound itself was redefined in 1959 by international agreement as exactly 0.45359237 kilograms. Since 1 kilogram = 1000 grams, one pound = 453.59237 grams. Dividing that by 16 gives 28.349523125 grams per ounce.

This is an exact definition, not an approximation. However, in practice, you will often see rounded versions:

• 1 oz = 28.35 g – common in cooking and nutrition labels.
• 1 oz = 28 g – a rough shortcut, often used in casual recipes.
• 1 oz = 28.3495 g – scientific and engineering contexts.

For most home use, the difference between 28.35 and 28.349523125 is negligible (about 0.0005 grams per ounce). But if you are measuring precious metals or doing precise chemistry, use the exact factor.

When to Use This Conversion

You will need grams-to-ounces conversion in many everyday situations:

• Cooking and baking – many European recipes list ingredients in grams, while US recipes use ounces. Converting accurately prevents failed baked goods.
• Nutrition and diet tracking – food labels in different countries use different units; converting helps compare portions.
• Shipping and postage – postal rates often depend on weight in ounces, but your kitchen scale might read grams.
• Science and education – lab measurements, homework problems, and experiments frequently require unit conversion.
• Jewelry and metals – gold, silver, and gemstones are often weighed in grams internationally but in troy ounces in some markets. (Note: this calculator uses avoirdupois ounces, not troy ounces. Troy ounces are heavier: 1 troy oz = 31.1034768 g. If you are weighing precious metals, use a troy-ounce converter instead.)

Common Mistakes and How to Avoid Them

Unit conversion errors are easy to make, especially when you are in a hurry. Here are the most frequent pitfalls:

• Using the wrong ounce – Avoirdupois ounces (28.35 g) are for everyday weight. Troy ounces (31.10 g) are for precious metals. Fluid ounces are a measure of volume, not weight – 1 fluid ounce of water weighs about 1.04 ounces, but 1 fluid ounce of oil weighs less. Never mix these up.
• Rounding too early – If you round 28.3495 to 28 before dividing, you will be off by about 1.2% (for 250 g, you would get 8.93 oz instead of 8.82 oz). That can matter in baking.
• Reversing the operation – To convert grams to ounces, you divide by 28.35. To convert ounces to grams, you multiply by 28.35. A quick sanity check: since 1 ounce is about 28 grams, 250 grams should be roughly 250/28 ≈ 9 ounces. If your answer is 7000, you multiplied instead of divided.
• Forgetting the zero – 100 g ≈ 3.5 oz, not 35 oz. Double-check your decimal point.

How to Convert Without a Calculator

If you don’t have a calculator handy, you can do a rough mental conversion:

1. Remember that 1 ounce ≈ 28.35 grams, or roughly 28 grams.
2. Divide the number of grams by 28. For example, 200 g ÷ 28 = 7.14 oz.
3. For a slightly more accurate estimate, divide by 28.35. For 200 g: 200 ÷ 28.35 = 7.05 oz.
4. If you need a very quick ballpark, remember that 30 g ≈ 1.06 oz, so 30 g is just over an ounce.

For exact conversions, use the calculator above or multiply grams by 0.03527396 (which is 1/28.349523125). For example, 250 g × 0.035274 = 8.8185 oz.

Frequently Asked Questions

How many grams are in an ounce?

There are exactly 28.349523125 grams in one avoirdupois ounce. For most everyday purposes, you can round this to 28.35 grams. If you are measuring precious metals, note that a troy ounce is heavier – 31.1034768 grams.

Is 100 grams equal to 3.5 ounces?

Yes, approximately. 100 grams divided by 28.3495 gives 3.527 ounces. Rounded to one decimal place, that is 3.5 ounces. Many nutrition labels round to 3.5 oz for a 100 g serving.

What is the difference between fluid ounces and ounces?

Fluid ounces (fl oz) measure volume – how much space a liquid takes up. Ounces (oz) measure weight – how heavy something is. One fluid ounce of water weighs about 1.043 ounces, but one fluid ounce of honey weighs about 1.5 ounces because honey is denser. You cannot convert grams to fluid ounces without knowing the density of the substance.

Why do some recipes use grams instead of ounces?

Grams are part of the metric system, which is used in most countries worldwide. Metric measurements are based on powers of 10, making them easier to scale and convert. In baking especially, grams are more precise than cups or ounces because weight doesn’t change with how you scoop or pack an ingredient. Many professional bakers prefer grams for consistency.

How do I convert pounds and ounces to grams?

First, convert the pounds to ounces (1 pound = 16 ounces), then add the remaining ounces, and finally multiply by 28.3495. For example, 1 lb 8 oz = 16 + 8 = 24 oz; 24 × 28.3495 = 680.4 grams. To go the other way, divide grams by 28.3495 to get total ounces, then divide that by 16 to get pounds with a remainder.

Is a gram or an ounce bigger?

An ounce is much bigger than a gram. One ounce equals about 28.35 grams. So if you have 1 ounce of something, you have roughly 28 times more mass than if you had 1 gram. A paperclip weighs about 1 gram, while a slice of bread weighs about 28 grams (1 ounce).

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in g | Grams | g | 250 | 0
out oz | Ounces | oz | g / 28.349523125 | 3
out lb_oz | Pounds + Ounces | lb+oz | floor(g / 453.59237) | 0