mmol, IU and per mille
mmol, IU (international units) and ratios
How to calculate with mmol, IU (international units), per mille and ratios such as 1:1000.
mmol and mol
A mole is a way of counting particles instead of weighing them.
To move between weight and moles you need the molar mass (g/mol) of the substance.
1000 ÷ 58.5 ≈ 17.1 mmol
1 mol = 1000 mmol. The molar mass is given in the question or in a reference table.
IU (international units)
IU measure biological effect, not weight.
There is no general conversion between IU and mg. The strength is stated for each product, for example IU/mL, and you use it like any other strength.
Per mille and ratios
Concentration can be written in several ways.
| Notation | Equals | Means |
|---|---|---|
| 1 % | 10 mg/mL | 1 g per 100 mL |
| 1 ‰ (per mille) | 1 mg/mL | 1 g per 1000 mL |
| 1:1000 | 1 mg/mL | 1 g per 1000 mL |
| 1:10,000 | 0.1 mg/mL | 1 g per 10,000 mL |
See also percentage solutions for calculating with percentage solutions.
Frequently asked questions
How do you convert mg to mmol?+
Divide the mg by the substance's molar mass in g/mol. The answer is in mmol.
Can you convert IU to mg?+
No, not in general. IU measure biological effect, and the strength is stated for each product, for example IU/mL.
What does 1:1000 mean?+
1 gram in 1000 mL, which is 1 mg/mL.
How many mg/mL is 1 per mille?+
1 per mille is 1 mg/mL.
Practise concentrations and units
Practise concentrations and units in practice questions and use the statistics to see how you are getting on. Dos is a practice app for drug calculations, with practice tests of ten questions, a built-in calculator next to each question and statistics per topic.
