Convert Ounces to Gram – Ounces to Grams Calculator

Need a quick answer? 1 avoirdupois ounce (oz) equals exactly 28.349523125 grams (g). Enter any weight in ounces below and the calculator will convert it to grams using the full conversion factor.

This calculator is for ounces of weight, not fluid ounces. For everyday food, package and general weight measurements, “oz” normally refers to the avoirdupois ounce.

Convert ounces to grams

oz Convert oz to g

g

If you need to convert ounces to gram measurements, the calculation is straightforward: 1 ounce equals exactly 28.349523125 grams when using the standard avoirdupois ounce. Enter your value in the calculator above for an instant result, or use the formula, examples and conversion chart below to calculate ounces to grams manually.

Quick answer:

1 oz = 28.349523125 g

For most everyday purposes:

1 oz ≈ 28.35 g

The calculator on this page uses the full conversion factor rather than the rounded 28.35 value.

How to Convert Ounces to Grams Measurements

To convert ounces to grams, multiply the number of ounces by 28.349523125.

Ounces to grams formula

grams = ounces × 28.349523125

Or, using unit symbols:

g = oz × 28.349523125

For example, to convert 5 ounces to grams:

5 × 28.349523125 = 141.747615625 g

Therefore:

5 oz ≈ 141.75 g

when rounded to two decimal places.

For quick everyday calculations, multiplying by 28.35 is usually sufficient. For calculations where greater precision matters, use the full conversion factor or the calculator above.

Common Ounces to Grams Conversions

Here are some useful values that frequently occur in cooking, food packaging and everyday weight measurements:

An especially useful relationship to remember is:

16 oz = 1 lb = 453.59237 g

This is because there are exactly 16 avoirdupois ounces in one avoirdupois pound.

What Is an Ounce?

An ounce, abbreviated oz, is a unit of mass used primarily in the United States and in some contexts in countries that still use Imperial or customary measurements.

The ounce used for ordinary weights is normally the avoirdupois ounce.

One avoirdupois ounce is:

1 oz = 28.349523125 g

and:

16 oz = 1 lb

This distinction matters because “ounce” can refer to more than one measurement system.

Avoirdupois ounce vs troy ounce

The standard ounce used for groceries, food portions, packages and most everyday objects is the avoirdupois ounce.

A troy ounce, however, is different:

1 troy ounce ≈ 31.1034768 g

Troy ounces are primarily used for precious metals such as gold and silver.

Therefore, if you are converting the weight of gold, silver or another precious metal, you should not use a standard ounces-to-grams calculator unless the measurement is specifically stated in avoirdupois ounces.

What Is a Gram?

A gram, abbreviated g, is a metric unit of mass.

The kilogram is the SI base unit of mass, and:

1 gram = 0.001 kilogram

or:

1 kilogram = 1,000 grams

Grams are particularly convenient for relatively small masses. They are widely used for food ingredients, nutrition information, product weights, laboratory measurements and many everyday objects.

Because metric measurements are widely used internationally, converting ounces to grams is particularly useful when moving between U.S. customary and metric measurements.

Why Is It Useful to Convert Ounces to Grams Values?

The need to convert ounces to gram values occurs frequently because ounces and grams belong to different measurement systems.

Cooking and baking

One of the most common situations is following a recipe from another country.

A U.S. recipe may specify:

4 oz of an ingredient

while a digital kitchen scale or an international recipe may use grams.

The conversion is:

4 × 28.349523125 = 113.3980925 g

So 4 oz is approximately 113.4 grams.

Weight-based measurements can be particularly useful in baking because weighing ingredients can provide more consistent results than estimating quantities by volume.

Food packaging and portion sizes

Product labels and food packages may display weights in ounces, grams or both.

Knowing the conversion makes it easier to compare products or understand package sizes when shopping internationally.

For example:

8 oz ≈ 226.8 g

and:

16 oz ≈ 453.6 g

Shipping and small packages

Ounces are often used for lightweight items and packages in the United States, while international shipping documentation may use grams or kilograms.

Being able to convert between the two systems makes it easier to compare weight limits or prepare measurements for different services.

Education and technical work

Students and professionals may also encounter measurements expressed in different systems.

Using the exact conversion factor allows measurements to be translated consistently between ounces and metric units.

Ounces Are Not the Same as Fluid Ounces

This is one of the most important distinctions on this page.

Ounces (oz) measure mass.

Fluid ounces (fl oz) measure volume.

Therefore:

1 oz → grams

is a direct mass conversion.

But:

1 fl oz → grams

cannot be converted with one universal factor because the answer depends on the density of the substance.

For example, a fluid ounce of water and a fluid ounce of oil occupy a similar volume but do not necessarily have the same mass.

If your measurement says fl oz, use a fluid-volume converter rather than this weight converter.

How Accurate Should an Ounces to Grams Conversion Be?

The appropriate number of decimal places depends on what you are measuring.

The exact conversion factor used on this page is:

1 oz = 28.349523125 g

However, displaying every decimal place is not always useful.

For everyday purposes:

1 oz ≈ 28.35 g

For kitchen measurements, rounding to the nearest gram or tenth of a gram may often be sufficient depending on the ingredient and scale.

For calculations requiring greater precision, keep more decimal places and avoid repeatedly rounding intermediate values.

Our calculator performs the conversion using the full factor and only formats the displayed result afterward.

Worked Examples

Example 1: Convert 2 oz to grams

Use the formula:

grams = ounces × 28.349523125

Therefore:

2 × 28.349523125 = 56.69904625

So:

2 oz ≈ 56.70 g

Example 2: Convert 8 oz to grams

8 × 28.349523125 = 226.796185

Therefore:

8 oz ≈ 226.80 g

Example 3: Convert 16 oz to grams

16 × 28.349523125 = 453.59237

Therefore:

16 oz = 453.59237 g

This is also one pound.

Example 4: Convert 25 oz to grams

25 × 28.349523125 = 708.738078125

Therefore:

25 oz ≈ 708.74 g

Example 5: Convert 100 oz to grams

100 × 28.349523125 = 2,834.9523125

Therefore:

100 oz ≈ 2,834.95 g

or approximately:

2.835 kg

Can I Convert Ounces to Grams Without a Calculator?

Yes.

For a quick mental estimate, multiply ounces by approximately 28.35.

For example, for 10 ounces:

10 × 28.35 = 283.5 g

The more precise result is:

10 oz = 283.49523125 g

The difference is tiny for ordinary everyday measurements.

For larger quantities or when precision matters, use the calculator rather than repeatedly estimating.

Understanding Rounding

A conversion can be mathematically correct while being displayed at different levels of precision.

For example:

1 oz = 28.349523125 g

may be displayed as:

• 28.35 g to two decimal places
• 28.350 g to three decimal places
• 28 g to the nearest whole gram

None of these automatically means the underlying conversion factor has changed. They simply represent different levels of rounding.

On Easy Unit Convert, we use the full conversion factor for the calculation whenever practical and round displayed examples to a useful number of decimal places.

Accuracy and Conversion Standard

This page uses the avoirdupois ounce, which is the standard ounce used for most ordinary weight measurements.

The conversion factor used here is:

1 avoirdupois ounce = 28.349523125 grams

This value is consistent with conversion tables published by the U.S. National Institute of Standards and Technology (NIST).

For information about how Easy Unit Convert checks formulas, conversion factors and rounding, see our Accuracy & Editorial Policy.

Ounces to Grams Conversion Table

The table below uses the full conversion factor of 28.349523125 grams per avoirdupois ounce. Results are rounded to three decimal places for easy reference.

Ounces (oz)	Grams (g)
1 oz	28.350 g
10 oz	283.495 g
20 oz	566.990 g
30 oz	850.486 g
40 oz	1,133.981 g
50 oz	1,417.476 g
60 oz	1,700.971 g
70 oz	1,984.467 g
80 oz	2,267.962 g
90 oz	2,551.457 g
100 oz	2,834.952 g

Related Weight Converters

If you need to move between related weight units, you may also find these useful:

• Convert Grams to Ounces
• Convert kg to lbs
• Convert lbs to kg
• Convert Kilograms to Stones

Frequently Asked Questions

Sources and measurement references

The conversion factor used on this page is based on recognized measurement standards.

• NIST Handbook 44, Appendix C – General Tables of Units of Measurement: lists 1 avoirdupois ounce as exactly 0.028349523125 kilograms, or 28.349523125 grams.
• BIPM – The International System of Units (SI): identifies the kilogram as the SI base unit of mass.

For more information about how conversion factors are checked and rounded on Easy Unit Convert, see our Accuracy & Editorial Policy.