Pounds To Milligrams Conversion (lb To Mg) - Inch Calculator

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• Pounds to Milligrams Converter
• How to Convert Pounds to Milligrams
• How Many Milligrams Are in a Pound?
• What Is a Pound?
• What Is a Milligram?
• Pound 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.). Pounds to Milligrams Converter. Inch Calculator. Retrieved February 9, 2026, from https://www.inchcalculator.com/convert/pound-to-milligram/

How to Convert Pounds to Milligrams

To convert a measurement in pounds to a measurement in milligrams, multiply the weight by the following conversion ratio: 453,592.37 milligrams/pound.

Since one pound is equal to 453,592.37 milligrams, you can use this simple formula to convert:

milligrams = pounds × 453,592.37

The weight in milligrams is equal to the weight in pounds multiplied by 453,592.37.

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

milligrams = (5 lb × 453,592.37) = 2,267,961.85 mg

How Many Milligrams Are in a Pound?

There are 453,592.37 milligrams in a pound, which is why we use this value in the formula above.

1 lb = 453,592.37 mg

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

What Is a Pound?

Pounds are a widely used unit of weight in the United States. The National Bureau of Standards approved the international definition of the pound for use in the United States in 1959 after an agreement between six nations referred to as the International Yard and Pound Agreement.[1]

One pound is equal to 16 ounces, or 0.45359237 kilograms. In the avoirdupois or apothecaries' systems, one pound is equal to 7,000 grains.[2]

The pound is a US customary and imperial unit of weight. A pound is sometimes also referred to as a common ounce. Pounds can be abbreviated as lb (plural lbs), and are also sometimes abbreviated as lbm or #. For example, 1 pound can be written as 1 lb, 1 lbm, or 1 #, and 2 pounds can be written as 2 lbs.

Learn more about pounds.

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.

Pound to Milligram Conversion Table

Table showing various pound measurements converted to milligrams.

Pounds	Milligrams
0.00001 lb	4.5359 mg
0.00002 lb	9.0718 mg
0.00003 lb	13.61 mg
0.00004 lb	18.14 mg
0.00005 lb	22.68 mg
0.00006 lb	27.22 mg
0.00007 lb	31.75 mg
0.00008 lb	36.29 mg
0.00009 lb	40.82 mg
0.000001 lb	0.453592 mg
0.00001 lb	4.5359 mg
0.0001 lb	45.36 mg
0.001 lb	453.59 mg
0.01 lb	4,536 mg
0.1 lb	45,359 mg
1 lb	453,592 mg

References

1. National Bureau of Standards, Refinement of Values for the Yard and Pound, U.S. Department of Commerce, July 1, 1959, https://www.nist.gov/system/files/documents/2017/05/09/frn-59-5442-1959.pdf
2. Encyclopædia Britannica, Avoirdupois weight, https://www.britannica.com/science/avoirdupois-weight

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