If you have ever followed a recipe, checked a food label, weighed a package, or compared measurements from different countries, you may have asked: how many grams are in an ounce?
The standard answer is:
1 ounce = 28.3495 grams
For most everyday purposes, this is commonly rounded to:
1 ounce ≈ 28.35 grams
And in simple cooking situations, people may even round it to:
1 ounce ≈ 28 grams
Knowing how to convert ounces to grams is useful because ounces are commonly used in the United States, while grams are widely used around the world.
The calculation is simple once you know the conversion factor.
In this guide, you will learn the exact number of grams in an ounce, how to convert ounces to grams and grams back to ounces, how common ounce measurements compare, and why a troy ounce is different from a regular ounce.
How Many Grams Are in One Ounce?
One standard ounce equals:
1 oz = 28.349523125 grams
For practical use, this is normally written as:
1 oz = 28.35 g
So if you are weighing food, ingredients, household items, or other everyday objects, you can usually use 28.35 grams per ounce.
For example:
- 1 ounce = 28.35 grams
- 2 ounces = 56.70 grams
- 3 ounces = 85.05 grams
- 4 ounces = 113.40 grams
- 8 ounces = 226.80 grams
- 16 ounces = 453.59 grams
The ounce used here is called the avoirdupois ounce. It is the standard ounce used for most ordinary weight measurements in the United States.
Quick answer
If you only need the conversion:
1 ounce = 28.35 grams
For rough kitchen estimates:
1 ounce ≈ 28 grams
For accurate measurements:
1 ounce = 28.3495 grams
How to Convert Ounces to Grams
To convert ounces into grams, multiply the number of ounces by 28.3495.
The formula is:
Grams = Ounces × 28.3495
Example: Convert 2 ounces to grams
Multiply:
2 × 28.3495 = 56.699
Therefore:
2 ounces ≈ 56.70 grams
Example: Convert 5 ounces to grams
5 × 28.3495 = 141.7475
So:
5 ounces ≈ 141.75 grams
Example: Convert 10 ounces to grams
10 × 28.3495 = 283.495
Therefore:
10 ounces ≈ 283.50 grams
Example: Convert 0.5 ounce to grams
Half an ounce is:
0.5 × 28.3495 = 14.17475
Therefore:
½ ounce ≈ 14.17 grams
For everyday calculations, you can usually round to two decimal places.
Ounces to Grams Conversion Chart
The following chart gives common ounce-to-gram conversions.
| Ounces | Grams |
|---|---|
| 0.25 oz | 7.09 g |
| 0.5 oz | 14.17 g |
| 1 oz | 28.35 g |
| 1.5 oz | 42.52 g |
| 2 oz | 56.70 g |
| 3 oz | 85.05 g |
| 4 oz | 113.40 g |
| 5 oz | 141.75 g |
| 6 oz | 170.10 g |
| 7 oz | 198.45 g |
| 8 oz | 226.80 g |
| 10 oz | 283.50 g |
| 12 oz | 340.19 g |
| 16 oz | 453.59 g |
| 20 oz | 566.99 g |
| 24 oz | 680.39 g |
| 32 oz | 907.18 g |
This table can be useful when converting recipes, food portions, shipping weights, and product measurements.
Common fractions of an ounce
Fractions are also easy to convert.
¼ ounce
28.3495 ÷ 4 = 7.0874
So:
¼ oz ≈ 7.09 grams
½ ounce
28.3495 ÷ 2 = 14.1748
So:
½ oz ≈ 14.17 grams
¾ ounce
28.3495 × 0.75 = 21.2621
So:
¾ oz ≈ 21.26 grams
These smaller measurements are particularly useful in cooking and ingredient preparation.
How to Convert Grams Back to Ounces
Sometimes you need to do the opposite conversion.
If you have grams and want ounces, divide the number of grams by 28.3495.
The formula is:
Ounces = Grams ÷ 28.3495
Example: Convert 100 grams to ounces
100 ÷ 28.3495 = 3.527
Therefore:
100 grams ≈ 3.53 ounces
Example: Convert 250 grams to ounces
250 ÷ 28.3495 = 8.818
So:
250 grams ≈ 8.82 ounces
Example: Convert 500 grams to ounces
500 ÷ 28.3495 = 17.637
Therefore:
500 grams ≈ 17.64 ounces
Example: Convert 1,000 grams to ounces
Since 1,000 grams equals one kilogram:
1,000 ÷ 28.3495 ≈ 35.27
So:
1 kilogram ≈ 35.27 ounces
Here is a quick reference chart:
| Grams | Ounces |
|---|---|
| 10 g | 0.35 oz |
| 25 g | 0.88 oz |
| 50 g | 1.76 oz |
| 100 g | 3.53 oz |
| 150 g | 5.29 oz |
| 200 g | 7.05 oz |
| 250 g | 8.82 oz |
| 500 g | 17.64 oz |
| 750 g | 26.46 oz |
| 1,000 g | 35.27 oz |
The easiest rule to remember is:
Ounces to grams: multiply by 28.3495
Grams to ounces: divide by 28.3495
Why Does One Ounce Equal 28.35 Grams?
The reason comes from the relationship between the avoirdupois system and the modern international definition of the pound.
A standard avoirdupois pound contains:
16 ounces
A pound is exactly:
453.59237 grams
Therefore:
453.59237 ÷ 16 = 28.349523125 grams
That gives us the exact standard conversion:
1 ounce = 28.349523125 grams
This value is often shortened to:
28.35 grams
The avoirdupois system is commonly used for everyday weight measurements such as:
- Food
- Packaged goods
- Body weight
- Household products
- Shipping items
- Commercial goods
This is the ounce most people mean when they ask how many grams are in an ounce.
Regular Ounce vs Troy Ounce: What Is the Difference?
One of the most important things to understand is that not every ounce has the same weight.
For ordinary goods, the standard ounce is the avoirdupois ounce.
But precious metals are commonly measured using the troy ounce.
Standard ounce
A standard avoirdupois ounce equals:
28.3495 grams
This is used for normal everyday weights.
Troy ounce
A troy ounce equals approximately:
31.1035 grams
This unit is commonly used for precious metals such as:
- Gold
- Silver
- Platinum
- Palladium
That means:
1 regular ounce ≈ 28.35 grams
while:
1 troy ounce ≈ 31.10 grams
The difference is about:
2.75 grams
That may not seem large, but it can be significant when calculating the value of precious metals.
Quick comparison
| Type of Ounce | Grams |
|---|---|
| Standard avoirdupois ounce | 28.3495 g |
| Troy ounce | 31.1035 g |
So if you are converting the weight of food, clothing, parcels, or household items, use 28.35 grams per ounce.
If you are working with gold or other precious metals, check whether the measurement is given in troy ounces.
Practical Ounce-to-Gram Examples
Understanding the conversion becomes easier when you see how it works in everyday situations.
Cooking
Suppose a recipe calls for:
4 ounces of cheese
Convert it to grams:
4 × 28.3495 = 113.398
So:
4 ounces ≈ 113.4 grams
If a recipe calls for 8 ounces:
8 × 28.3495 = 226.796
Therefore:
8 ounces ≈ 226.8 grams
Meat portions
A common food portion may be listed as 6 ounces.
Convert:
6 × 28.3495 = 170.097
So:
6 ounces ≈ 170 grams
Baking
A baking recipe from the United States might list an ingredient as 3 ounces.
Convert:
3 × 28.3495 = 85.0485
Therefore:
3 ounces ≈ 85.05 grams
Using grams can be especially convenient in baking because a digital kitchen scale often provides more consistent measurements.
Package weight
Suppose a product weighs 12 ounces.
Convert:
12 × 28.3495 = 340.194
So:
12 ounces ≈ 340.19 grams
16 ounces
Since 16 ounces equal one pound:
16 oz = 453.592 grams
Therefore:
16 ounces ≈ 453.59 grams
This is also why one pound is approximately 454 grams.
Ounces, Grams, Pounds, and Kilograms Explained
Understanding how these common weight units relate can make conversions much easier.
Ounces and pounds
There are:
16 ounces in 1 pound
Therefore:
1 pound = 16 ounces
Since one ounce equals 28.3495 grams:
16 × 28.3495 ≈ 453.59 grams
So:
1 pound ≈ 453.59 grams
Grams and kilograms
There are:
1,000 grams in 1 kilogram
Therefore:
1 kg = 1,000 g
Since one ounce equals about 28.35 grams:
1 kilogram ≈ 35.27 ounces
Useful conversion table
| Measurement | Equivalent |
|---|---|
| 1 ounce | 28.3495 grams |
| 16 ounces | 1 pound |
| 1 pound | 453.592 grams |
| 1 kilogram | 1,000 grams |
| 1 kilogram | 35.274 ounces |
| 1 kilogram | 2.205 pounds |
These relationships are useful when switching between U.S. customary and metric measurements.
Tips for Accurate Ounce and Gram Conversions
The math is straightforward, but a few practical tips can improve accuracy.
- Use 28.3495 grams per ounce when precision is important.
- Use 28.35 grams for normal everyday calculations.
- Use 28 grams only when a rough estimate is acceptable.
- Check whether the ounce is a standard ounce or a troy ounce.
- Use a digital scale for cooking or baking when accurate weight matters.
- Do not confuse ounces of weight with fluid ounces.
- Round only at the end of your calculation when possible.
Do not confuse ounces with fluid ounces
This is a common mistake.
An ounce (oz) measures weight or mass.
A fluid ounce (fl oz) measures volume.
They are not the same thing.
For example:
1 ounce of flour by weight
and:
1 fluid ounce of water by volume
measure different properties.
So if a recipe says “fl oz,” you should use a volume conversion rather than the 28.35-grams-per-ounce formula.
Weight can vary by ingredient
If a recipe gives an amount in fluid ounces, you cannot simply convert it to grams without knowing the ingredient.
Different ingredients have different densities.
However, if a recipe gives a true weight measurement in ounces, you can convert directly using:
1 oz = 28.3495 g
Frequently Asked Questions
How many grams are in 1 ounce?
There are exactly 28.349523125 grams in one standard avoirdupois ounce.
For most purposes:
1 ounce ≈ 28.35 grams
Is 1 ounce 28 grams or 30 grams?
Neither is exact.
The exact standard conversion is:
1 ounce = 28.3495 grams
You may round this to 28 grams for rough estimates, but 30 grams is less accurate.
How many grams are in half an ounce?
Half an ounce equals approximately:
14.17 grams
Calculation:
28.3495 ÷ 2 = 14.17475
How many grams are in a quarter ounce?
A quarter ounce equals approximately:
7.09 grams
How many grams are in 2 ounces?
2 ounces ≈ 56.70 grams
How many grams are in 3 ounces?
3 ounces ≈ 85.05 grams
How many grams are in 4 ounces?
4 ounces ≈ 113.40 grams
How many grams are in 5 ounces?
5 ounces ≈ 141.75 grams
How many grams are in 6 ounces?
6 ounces ≈ 170.10 grams
How many grams are in 8 ounces?
8 ounces ≈ 226.80 grams
How many grams are in 10 ounces?
10 ounces ≈ 283.50 grams
How many grams are in 12 ounces?
12 ounces ≈ 340.19 grams
How many grams are in 16 ounces?
16 ounces ≈ 453.59 grams
Sixteen ounces also equal one pound.
How many ounces are in 100 grams?
100 grams equal approximately:
3.53 ounces
How many ounces are in 250 grams?
250 grams equal approximately:
8.82 ounces
How many ounces are in 500 grams?
500 grams equal approximately:
17.64 ounces
How many ounces are in 1 kilogram?
One kilogram equals approximately:
35.27 ounces
How many grams are in a troy ounce?
One troy ounce equals approximately:
31.1035 grams
A troy ounce is mainly used to measure precious metals.
Is a gold ounce the same as a regular ounce?
Not usually.
Gold is commonly measured in troy ounces.
A troy ounce equals approximately:
31.1035 grams
A standard everyday ounce equals approximately:
28.3495 grams
Is an ounce the same as a fluid ounce?
No.
An ounce measures weight or mass, while a fluid ounce measures volume.
They require different types of conversion.
What is the easiest way to convert ounces to grams?
Multiply the number of ounces by:
28.3495
For example:
7 oz × 28.3495 ≈ 198.45 g
What is the easiest way to convert grams to ounces?
Divide the number of grams by:
28.3495
For example:
200 g ÷ 28.3495 ≈ 7.05 oz
Conclusion
So, how many grams are in an ounce?
For the standard ounce used in everyday measurements:
1 ounce = 28.3495 grams
For most practical calculations, you can round this to:
1 ounce ≈ 28.35 grams
The easiest formulas to remember are:
Ounces × 28.3495 = Grams
and:
Grams ÷ 28.3495 = Ounces
For quick reference:
- ¼ oz ≈ 7.09 g
- ½ oz ≈ 14.17 g
- 1 oz ≈ 28.35 g
- 2 oz ≈ 56.70 g
- 4 oz ≈ 113.40 g
- 8 oz ≈ 226.80 g
- 16 oz ≈ 453.59 g
The main exception is the troy ounce, which equals approximately 31.1035 grams and is commonly used for gold and other precious metals.
For food, packages, household products, and most everyday measurements, however, the number you need to remember is simple:
1 ounce = approximately 28.35 grams.
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