Convert Ounce to Milligram
Turn Ounces into Milligrams in an instant. Type a value below to get an accurate oz → mg result, with the formula and a quick-reference table.
1 oz = 28,349.523 mg
Quick answer: 1 Ounce = 28,349.523 Milligram
Ounce to Milligram conversion table
| Ounce (oz) | Milligram (mg) |
|---|---|
| 1 oz | 28,349.523 mg |
| 2 oz | 56,699.046 mg |
| 5 oz | 141,747.62 mg |
| 10 oz | 283,495.23 mg |
| 20 oz | 566,990.46 mg |
| 50 oz | 1,417,476.2 mg |
| 100 oz | 2,834,952.3 mg |
| 500 oz | 14,174,762 mg |
| 1,000 oz | 28,349,523 mg |
How to convert Ounce to Milligram
To convert Ounces to Milligrams, multiply the value by 28,349.523.
- Take your measurement in Ounces.
- Multiply it by 28,349.523 — the number of Milligrams in one Ounce.
- The result is the same amount, expressed in Milligrams.
To go the other way, multiply Milligrams by 0.000035273962 — or simply divide by 28,349.523.
For example, one pound is about 16 oz, which is 453,592.37 mg.
About Ounce and Milligram
An ounce is an imperial unit of mass equal to about 28.35 grams, or one-sixteenth of a pound. It is common in the United States for food packaging, postage and cooking.
A milligram is one-thousandth of a gram (1/1000 g), a unit for very small masses. It is used for medicine doses, vitamins and nutritional amounts.
The Ounce is a imperial / US customary unit while the Milligram comes from the metric system — which is exactly why this conversion comes up so often. One Ounce equals 28,349.523 Milligrams.
Other weight & mass conversions
Frequently asked questions
How many Milligrams are in a Ounce?
1 Ounce equals 28,349.523 Milligram (oz → mg). To convert any amount, multiply the number of Ounces by 28,349.523.
How do I convert Ounce to Milligram?
Enter the number of Ounces in the converter above and read the result in Milligrams. It applies the exact oz → mg factor instantly, with full precision.
Is the Ounce to Milligram converter free?
Yes — it is completely free and unlimited, needs no sign-up, and runs right in your browser, so it is instant and private.
Is the conversion accurate?
Yes. It uses the internationally defined weight & mass factors and full floating-point precision, then rounds the display to a clean, readable number.