Units and measures
Six units appear in this arithmetic. Two of them are not quantities of anything until something else is known.
Educational arithmetic only. Not medical advice and not a dosing protocol.
| Unit | Equals | Equals | Measures |
|---|---|---|---|
| 1 g | 1,000 mg | 1,000,000 mcg | mass |
| 1 mg | 1,000 mcg | 1,000,000 ng | mass |
| 1 mcg | 1,000 ng | 0.001 mg | mass |
| 1 L | 1,000 mL | 1,000,000 microlitres | volume |
| 1 mL | 1,000 microlitres | 0.001 L | volume |
| 1 mmol | 1,000 micromoles | 1,000,000 nanomoles | amount of substance |
Read this with the answer
This is educational arithmetic on figures entered by the reader. It is not medical advice, not a dosing protocol, and not a recommendation that anything be prepared, obtained or administered.
Nothing here states what quantity is appropriate for anyone, and there is no function in it that produces an amount to administer. A question about anyone’s health belongs with a licensed clinician who can examine the person asking.
Most compounds named here are research chemicals that are not approved by the FDA for human use. An exact calculation is not an accurate measurement: what is actually in a syringe depends on the preparation and the device, neither of which this page can see.
No qualified clinical reviewer is recorded against this site, and no credential is claimed anywhere on it. Full disclaimer.
The four that convert on their own
Grams, milligrams, micrograms and nanograms are all mass, related by exact powers of a thousand. Litres, millilitres and microlitres are all volume, likewise. Converting between any two of them needs nothing beyond the definition, and the conversion is exact.
Moles are a count of molecules expressed in a convenient unit, and millimoles, micromoles and nanomoles relate to each other the same exact way. What is not free is getting from a mass to a molar amount, which needs the molar mass of the particular compound.
The two that do not
A syringe unit is a volume only once the barrel is known
"20 units" is 0.2 mL on a U-100 barrel, 0.4 mL on a U-50 and 0.5 mL on a U-40. The unit is a mark on a device, and the volume behind the mark is set by how that device was calibrated. Nothing about the number alone identifies a volume. Syringe scales sets out the three calibrations.
An international unit is an activity, not a mass
An IU is defined per substance, against a biological reference standard, and the milligrams-per-IU figure belongs to the particular preparation it was measured in. There is no universal conversion, and this site holds no IU table: the converter asks for the figure from the preparation's own documentation and does the arithmetic on that.
Why a mass is the wrong unit for comparing two compounds
A milligram of a small molecule and a milligram of a large one are not comparable amounts of substance. At 889 g/mol against 4,813 g/mol, the same mass holds about 5.4 times as many molecules in the first case. The molar amount is the figure that compares; the mass is the figure printed on the vial.
Each compound page carries a sourced molar mass and the record it came from, so that conversion can be made without anybody guessing the figure.