Enter the value in units and select the substance to determine the equivalent amount in milligrams (mg).

Units to mg Converter

IU Substances
Semaglutide
Medication
Use this mode only for true International Units.
5 units
10 units
20 units
25 units
30 units
50 units
100 units
This mode is for syringe-unit dosing math, not International Units.

Units to mg Formula

The following formula is used to convert a quantity in units (IU) into milligrams for a specific substance.

mg = units ร— (mg per unit)

Variables:

  • mg is the mass in milligrams
  • units is the quantity in International Units (IU)
  • mg per unit is the conversion factor for the selected substance

To calculate milligrams from units, multiply the number of units by the correct mg-per-unit conversion factor for that vitamin, hormone, or drug.

What is Units to mg Conversion?

Units to mg conversion is the process of changing a value expressed in International Units into an equivalent mass in milligrams. International Units measure biological activity rather than physical weight, which means the conversion depends entirely on the specific substance being measured. Because of this, 1000 IU of vitamin D does not equal the same number of milligrams as 1000 IU of vitamin E or insulin.

Common examples include vitamin Dโ‚ƒ, vitamin A, vitamin E, and insulin. Each has a standard IU definition that determines how much actual mass corresponds to one unit. Once that factor is known, the conversion is straightforward.

Common Units to mg Conversion Factors

  • Vitamin Dโ‚ƒ (cholecalciferol): 1 IU โ‰ˆ 0.000025 mg
  • Vitamin A (retinol): 1 IU โ‰ˆ 0.0003 mg
  • Vitamin A (ฮฒ-carotene): 1 IU โ‰ˆ 0.0006 mg
  • Vitamin E (d-alpha-tocopherol): 1 IU โ‰ˆ 0.671 mg
  • Vitamin E (dl-alpha-tocopherol): 1 IU โ‰ˆ 0.9 mg
  • Insulin (human standard): 1 IU โ‰ˆ 0.0347 mg

How to Convert Units to mg?

The following steps outline how to convert units into milligrams.


  1. First, determine the value in units (IU).
  2. Next, identify the substance being measured.
  3. Find the correct mg-per-unit conversion factor for that substance.
  4. Multiply the units by the mg-per-unit factor using the formula mg = units ร— (mg per unit).
  5. Check your answer with the calculator above.

Example Problem : 

Convert 1000 IU of vitamin Dโ‚ƒ into milligrams.

Units = 1000 IU

Conversion Factor = 0.000025 mg per IU

mg = 1000 ร— 0.000025 = 0.025 mg

Units to mg Conversion Table

The table below shows example conversions for 1000 IU of several common substances.

SubstanceApprox. mg per 1 IU1000 IU in mg
Vitamin Dโ‚ƒ (cholecalciferol)0.000025 mg0.025 mg
Vitamin A (retinol)0.0003 mg0.3 mg
Vitamin A (ฮฒ-carotene)0.0006 mg0.6 mg
Vitamin E (d-alpha-tocopherol)0.671 mg671 mg
Vitamin E (dl-alpha-tocopherol)0.9 mg900 mg
Insulin (human standard)0.0347 mg34.7 mg

In practice, always verify the exact conversion standard for the product or reference you are using. IU values are substance-specific, so the correct answer depends on selecting the right compound before converting units to mg.