HCG
International units, not milligrams.
HCG is measured in international units rather than milligrams, which breaks every conversion habit built on mg and mcg. The division is the same, the labels are not.
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The science
Why international units change nothing and everything
01
HCG is supplied as a powder labelled in international units, typically 5,000 or 10,000 IU per vial, and reconstituted with a diluent before injection. An international unit is a measure of biological activity rather than mass, which is why the label does not give you milligrams.
02
Mathematically this changes nothing. Concentration is still vial contents divided by diluent volume, and a dose is still that concentration divided into the amount you want. A 5,000 IU vial in 2 ml is 2,500 IU per ml, so a 500 IU dose is 0.2 ml, which is 20 units on a U-100 barrel. The arithmetic does not care what the numerator is called, only that both figures use the same unit.
03
Practically it changes a great deal, because every conversion habit built around milligrams and micrograms stops applying. There is no factor of a thousand to remember, and no mg to mcg step to get wrong. There is also no way to convert an IU figure into a mass figure without compound specific information, so any attempt to mix the two units in one calculation is an error.
04
The numbers involved are also much larger, which matters for reading a calculator. Entering 5000 where other pages expect 5 feels wrong but is correct. The calculator above is relabelled for international units precisely so those large figures do not have to be mentally translated into a unit system they do not belong to.
Lookup
5,000 IU and 10,000 IU vials by diluent volume
The two common presentations, with every cell showing the mark on a U-100 barrel. Note that the column headings are millilitres of diluent, the same as anywhere else.
5000 mg HCG vial
Units on a U-100 syringe
| Dose | 1 ml | 1.5 ml | 2 ml | 2.5 ml | 3 ml |
|---|---|---|---|---|---|
| 250 IU | 5 | 7.5 | 10 | 12.5 | 15 |
| 500 IU | 10 | 15 | 20 | 25 | 30 |
| 1,000 IU | 20 | 30 | 40 | 50 | 60 |
| 1,500 IU | 30 | 45 | 60 | 75 | 90 |
| 2,000 IU | 40 | 60 | 80 | 100 | · |
10000 mg HCG vial
Units on a U-100 syringe
| Dose | 1 ml | 1.5 ml | 2 ml | 2.5 ml | 3 ml |
|---|---|---|---|---|---|
| 250 IU | 2.5 | 3.75 | 5 | 6.25 | 7.5 |
| 500 IU | 5 | 7.5 | 10 | 12.5 | 15 |
| 1,000 IU | 10 | 15 | 20 | 25 | 30 |
| 1,500 IU | 15 | 22.5 | 30 | 37.5 | 45 |
| 2,000 IU | 20 | 30 | 40 | 50 | 60 |
A dot marks a combination that falls under two units or overflows a 100-unit barrel. Both are hard to measure accurately, so they are worth avoiding rather than eyeballing.
Regulatory status
HCG is a prescription medicine
Unlike most compounds covered on this site, HCG is an approved prescription drug with published prescribing information covering its indications, dosing, diluent and preparation. That document is the authority, and it is supplied with the product.
This page therefore states no dose figures of its own. The tables show what a given number of international units measures as at a given dilution, which is arithmetic, and the amount itself is a matter for the prescription and the clinician behind it.
HCG is also widely sold outside that route, where the international unit figure on the label carries no verification. Because an international unit is defined by biological activity rather than mass, an unverified IU claim is harder to sanity check than an unverified milligram claim, and the arithmetic below inherits whatever error is in the label.
FAQ
Common questions
How many units is 500 IU of HCG?
It depends on the diluent volume. A 5,000 IU vial reconstituted with 2 ml gives 2,500 IU per ml, so 500 IU is 0.2 ml, which is 20 units on a U-100 syringe. The same vial in 1 ml gives 5,000 IU per ml, making 500 IU just 10 units. As always, the units figure only means something alongside the volume it came from.
How do I convert HCG IU to milligrams?
You generally cannot, and should not try. An international unit measures biological activity defined against a reference standard, not mass, so there is no universal conversion factor you can apply. Keep the entire calculation in international units. Mixing IU and mg in one sum is one of the few genuine arithmetic errors available in this space.
How much diluent should I add to a 5,000 IU HCG vial?
Follow the instructions supplied with your product, because HCG is a prescription medicine and the diluent and volume are specified. Where a range is permitted, more diluent puts small doses higher on the barrel and makes them easier to measure accurately. The tables above show where each volume lands so you can see the consequence of the choice.
Why does the calculator on this page say IU instead of mg?
Because HCG is labelled in international units and relabelling the fields is more honest than asking you to pretend a figure in IU is a figure in milligrams. The underlying division is identical to every other page on this site. Only the unit label differs, and the single dose unit option prevents an accidental thousand fold conversion being applied to a number that is not a mass.
Is HCG a prescription medicine?
Yes. HCG is an approved prescription drug with published prescribing information, supplied as a powder with a diluent, and used for specific indications including certain fertility treatments. That document rather than a website is the authority on dose and preparation. This page converts whichever figures apply to you into a mark on a barrel, and does not suggest a dose.
VialClock
This page calculates. Your notes app forgets.
Every tool here is stateless by design. What it cannot do is remember that your vial was mixed eleven days ago, or that a step-up is due this week.
Browse all calculatorsThis tool performs arithmetic on figures you enter, or presents a manufacturer-published schedule. It does not know your protocol, will never suggest a dose, and is not medical advice. Dosing decisions belong with a qualified prescriber.