How to use the ounces to grams converter
- Select the conversion direction: ounces to grams or grams to ounces.
- Type the value you want to convert into the input field.
- Read the converted result immediately below the input.
- Change the direction at any time to perform the reverse calculation.
How the ounces to grams conversion works
The international avoirdupois ounce is defined as exactly 28.349523125 grams. This definition was agreed upon by the United States and Commonwealth nations in 1959 and remains the standard for everyday weight measurements.
To convert ounces to grams, multiply the ounce value by that constant:
grams = ounces x 28.349523125
For example, 4 ounces equals 4 x 28.349523125 = 113.3980925 grams. To convert grams to ounces, divide instead:
ounces = grams / 28.349523125
So 100 grams divided by 28.349523125 gives approximately 3.5274 ounces. The converter above applies these formulas automatically when you switch between oz to g and g to oz.
Common ounce and gram equivalents
This reference table lists frequently used conversions for cooking, shipping and general measurement. Values are rounded to four decimal places where needed.
| Ounces (oz) | Grams (g) |
|---|---|
| 0.5 | 14.1748 |
| 1 | 28.3495 |
| 2 | 56.6990 |
| 4 | 113.3981 |
| 8 | 226.7962 |
| 16 (1 lb) | 453.5924 |
| 32 (2 lb) | 907.1847 |
If you need to work with larger weights, consider converting through pounds first. Sixteen ounces make one pound; see the pounds to ounces tool for that step.
Avoirdupois ounces versus fluid ounces
A common source of errors is confusing the avoirdupois ounce (a unit of mass) with the fluid ounce (a unit of volume). This converter handles only mass. A fluid ounce measures how much space a liquid occupies, not how heavy it is.
In the US customary system, one fluid ounce of water weighs roughly 1.043 avoirdupois ounces, but that ratio changes with every liquid because density varies. Cooking oil, honey and milk all have different masses per fluid ounce. If a recipe calls for "4 oz of butter," it almost always means 4 avoirdupois ounces by weight, which is about 113.4 grams. If it says "4 fl oz of milk," you need a volume measurement, not this tool.
Always check whether your source refers to weight or volume before converting ounces to grams.
Troy ounces are different
Precious metals such as gold, silver and platinum are measured in troy ounces, not avoirdupois ounces. One troy ounce equals exactly 31.1034768 grams, which is about 10 percent heavier than the standard ounce used here.
If you are weighing jewelry or bullion, do not use the standard ounces to grams factor of 28.349523125. Using the wrong ounce type will give you an incorrect valuation. This converter is intended for everyday items, food, postal weights and general science where the avoirdupois system applies.
Practical uses for converting oz to g
Converting between ounces and grams comes up constantly in daily life. Here are a few situations where an accurate oz to g conversion matters:
- Cooking and baking: Many international recipes list ingredients in grams, while American recipes use ounces. Precision matters especially in baking, where a few extra grams of flour can change the texture of bread.
- Postal shipping: Carriers often charge by the gram or ounce depending on the country. Converting accurately avoids overpaying or underestimating postage.
- Nutrition tracking: Food labels outside the United States show serving sizes in grams. Converting helps you match those values to a scale calibrated in ounces.
- Science and engineering: Laboratory work typically requires metric units. Converting sample weights from ounces to grams ensures consistency with SI standards.
Worked examples
Each result below was produced by the same code the tool runs, so you can check your own numbers against them.
| Example | Input | Result |
|---|---|---|
| 1 ounce to grams | Conversion direction: oz-to-g; Value: 1 | Grams: 28.349523125; Input: 1 oz |
| 100 grams to ounces | Conversion direction: g-to-oz; Value: 100 | Ounces: 3.527396195; Input: 100 g |
| 8 ounces to grams | Conversion direction: oz-to-g; Value: 8 | Grams: 226.796185; Input: 8 oz |
| 500 grams to ounces | Conversion direction: g-to-oz; Value: 500 | Ounces: 17.6369809748; Input: 500 g |
FAQ
How many grams are in one ounce?
One avoirdupois ounce equals exactly 28.349523125 grams. For most practical purposes, rounding to 28.35 grams is sufficient.
How do I convert grams to ounces?
Divide the gram value by 28.349523125. For example, 100 grams divided by 28.349523125 is approximately 3.5274 ounces.
Is a fluid ounce the same as an ounce?
No. A fluid ounce measures volume, while an avoirdupois ounce measures mass. This converter only handles mass. Converting fluid ounces to grams requires knowing the density of the specific liquid.
Why does my kitchen scale show a slightly different number?
Consumer scales round to the nearest gram or half gram and may have slight calibration drift. The exact mathematical conversion is 1 oz = 28.349523125 g, but a typical home scale will display 28 g or 28.5 g.
Are troy ounces the same as regular ounces?
No. A troy ounce, used for precious metals, equals 31.1034768 grams. A regular avoirdupois ounce equals 28.349523125 grams. Do not use this converter for gold or silver weights.
Can I convert negative ounces?
Physical mass cannot be negative, so this converter rejects negative inputs. If you are calculating a difference between two weights, take the absolute value first.
Reference pages
- Cooking conversions: cups to grams: baking ingredients with a chart and calculator.