Ounces To Milligrams Conversion (oz To Mg) - Inch Calculator

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• Ounces to Milligrams Converter
• How to Convert Ounces to Milligrams
• How Many Milligrams Are in an Ounce?
• What Is an Ounce?
• What Is a Milligram?
• Ounce to Milligram Conversion Table
• References

Person Icon By Joe Sexton

Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.

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Sexton, J. (n.d.). Ounces to Milligrams Converter. Inch Calculator. Retrieved December 3, 2025, from https://www.inchcalculator.com/convert/ounce-to-milligram/

How to Convert Ounces to Milligrams

To convert a measurement in ounces to a measurement in milligrams, multiply the weight by the following conversion ratio: 28,349.523125 milligrams/ounce.

Since one ounce is equal to 28,349.523125 milligrams, you can use this simple formula to convert:

milligrams = ounces × 28,349.523125

The weight in milligrams is equal to the weight in ounces multiplied by 28,349.523125.

For example, here's how to convert 5 ounces to milligrams using the formula above.

milligrams = (5 oz × 28,349.523125) = 141,747.615625 mg

How Many Milligrams Are in an Ounce?

There are 28,349.523125 milligrams in an ounce, which is why we use this value in the formula above.

1 oz = 28,349.523125 mg

Ounces and milligrams are both units used to measure weight. Keep reading to learn more about each unit of measure.

What Is an Ounce?

One ounce is a unit of mass/weight equal to 1/16 of a pound or 28.349523 grams. The common ounce should not be confused with the troy ounce, which is equal to 1/12 of a troy pound.[1]

The ounce is a US customary and imperial unit of weight. Ounces can be abbreviated as oz; for example, 1 ounce can be written as 1 oz.

Learn more about ounces.

What Is a Milligram?

The milligram is a unit of mass equal to 1/1,000 of a gram, or 0.0154 grains.

The milligram, or milligramme, is an SI unit of weight in the metric system. In the metric system, "milli" is the prefix for thousandths, or 10-3. Milligrams can be abbreviated as mg; for example, 1 milligram can be written as 1 mg.

Learn more about milligrams.

Ounce to Milligram Conversion Table

Table showing various ounce measurements converted to milligrams.

Ounces	Milligrams
0.0001 oz	2.835 mg
0.0002 oz	5.6699 mg
0.0003 oz	8.5049 mg
0.0004 oz	11.34 mg
0.0005 oz	14.17 mg
0.0006 oz	17.01 mg
0.0007 oz	19.84 mg
0.0008 oz	22.68 mg
0.0009 oz	25.51 mg
0.001 oz	28.35 mg
0.002 oz	56.7 mg
0.003 oz	85.05 mg
0.004 oz	113.4 mg
0.005 oz	141.75 mg
0.006 oz	170.1 mg
0.007 oz	198.45 mg
0.008 oz	226.8 mg
0.009 oz	255.15 mg
0.01 oz	283.5 mg
0.02 oz	566.99 mg
0.03 oz	850.49 mg
0.04 oz	1,134 mg
0.05 oz	1,417 mg
0.06 oz	1,701 mg
0.07 oz	1,984 mg
0.08 oz	2,268 mg
0.09 oz	2,551 mg
0.1 oz	2,835 mg
0.2 oz	5,670 mg
0.3 oz	8,505 mg
0.4 oz	11,340 mg
0.5 oz	14,175 mg
0.6 oz	17,010 mg
0.7 oz	19,845 mg
0.8 oz	22,680 mg
0.9 oz	25,515 mg
1 oz	28,350 mg

References

1. James Bucki, Troy Ounce vs. Ounce, The Spruce, https://www.thesprucecrafts.com/troy-ounce-vs-ounce-4588158

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