OptiPin
HCG dosage calculator
Mix your HCG vial and get the exact insulin-syringe units to draw for your target IU dose, plus concentration and doses per vial. Full reconstitution chart below.
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HCG reconstitution chart
The powder amount is fixed, so the water you add is the only thing that sets concentration. This chart covers the three common vial sizes against the four water volumes people usually pick. All unit figures assume a U-100 insulin syringe, where 100 units = 1 mL.
| Vial | BAC water | Concentration | IU per unit | 250 IU dose | 500 IU dose |
|---|---|---|---|---|---|
| 2,000 IU vial | |||||
| 2,000 IU | 1 mL | 2,000 IU/mL | 20 IU | 12.5 units | 25 units |
| 2,000 IU | 2 mL | 1,000 IU/mL | 10 IU | 25 units | 50 units |
| 2,000 IU | 3 mL | 667 IU/mL | 6.7 IU | 37.5 units | 75 units |
| 2,000 IU | 5 mL | 400 IU/mL | 4 IU | 62.5 units | 100 units |
| 5,000 IU vial | |||||
| 5,000 IU | 1 mL | 5,000 IU/mL | 50 IU | 5 units | 10 units |
| 5,000 IU | 2 mL | 2,500 IU/mL | 25 IU | 10 units | 20 units |
| 5,000 IU | 3 mL | 1,667 IU/mL | 16.7 IU | 15 units | 30 units |
| 5,000 IU | 5 mL | 1,000 IU/mL | 10 IU | 25 units | 50 units |
| 10,000 IU vial | |||||
| 10,000 IU | 1 mL | 10,000 IU/mL | 100 IU | 2.5 units | 5 units |
| 10,000 IU | 2 mL | 5,000 IU/mL | 50 IU | 5 units | 10 units |
| 10,000 IU | 3 mL | 3,333 IU/mL | 33.3 IU | 7.5 units | 15 units |
| 10,000 IU | 5 mL | 2,000 IU/mL | 20 IU | 12.5 units | 25 units |
Reading the extremes tells you how to choose: 10,000 IU in 1 mL puts a 250 IU dose at 2.5 units, where a half-unit misread is a 20% dosing error. The same dose from a 2,000 IU vial in 5 mL is 62.5 units, which is far harder to get wrong. If your doses are small, mix more dilute.
How to mix (reconstitute) HCG
HCG ships as a lyophilized powder that has to be reconstituted before use. The mixing itself is simple; the two things that actually matter are choosing your water volume up front and not damaging the hormone on the way in.
Bacteriostatic vs sterile water, and how long it keeps
Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which is what makes a vial multi-dose. Manufacturer labeling for common lyophilized HCG products states the reconstituted solution should be refrigerated at 2-8 °C and used within 30 days.
Sterile water has no preservative. A vial reconstituted with it is single-use and should be discarded after one dose, no matter how much is left. This is the single most common mixing mistake.
Keep the vial refrigerated and away from light, and do not freeze it. Discard it if the solution turns cloudy, discolours or shows particles. Always follow the labeling that came with your specific product, since it varies by manufacturer.
HCG dosing by context
HCG is a prescription medication and your dose is set by your prescriber, not by a chart. The ranges below are the ones commonly reported in the clinical literature, given only so you can sanity-check that you have entered a plausible number into the calculator above. They are not a recommendation, and the right dose for you may sit outside them.
| Context | Commonly reported range | Typical frequency |
|---|---|---|
| Testicular maintenance alongside TRT | 250-500 IU | 2-3× per week |
| Fertility / hypogonadotropic hypogonadism | 1,000-2,500 IU | 2-3× per week |
| Ovulation trigger (a separate clinical use) | 5,000-10,000 IU | single dose |
Note the spread: a trigger dose is twenty times a maintenance dose. That is exactly why the concentration on your vial matters more than the unit count you remember from last time.
HCG IU calculator: IU to mL and syringe units
HCG is measured in international units (IU), a measure of biological activity rather than weight. Converting IU to a volume you can draw takes one number: the concentration you created at mixing time. mL = dose in IU ÷ concentration in IU/mL, and units on a U-100 insulin syringe = mL × 100. The table below runs the three most common doses through the three most common concentrations.
| Dose | At 1,000 IU/mL | At 2,500 IU/mL | At 5,000 IU/mL |
|---|---|---|---|
| 250 IU | 0.25 mL · 25 units | 0.1 mL · 10 units | 0.05 mL · 5 units |
| 500 IU | 0.5 mL · 50 units | 0.2 mL · 20 units | 0.1 mL · 10 units |
| 1,000 IU | 1 mL · 100 units | 0.4 mL · 40 units | 0.2 mL · 20 units |
There is no universal IU-to-mL answer for HCG, which is why an IU calculator has to ask about your water volume first. If you did not label the vial at mixing time, the concentration cannot be recovered by looking at the liquid.
A free HCG calculator, built for IU (not a generic peptide calculator)
This is a free HCG reconstitution and dosage calculator: no login, no signup, no email, and it runs entirely in your browser. Nothing you enter leaves the page.
It is also deliberately not a generic peptide calculator. Most peptide reconstitution calculators expect the vial strength in mg or mcg, but HCG vials are labeled in IU, and there is no fixed weight conversion between the two. Forcing HCG through an mg-based tool means an error-prone conversion step before you even start. This page works in IU end to end. For mg-based compounds like BPC-157, semaglutide or tirzepatide, use the peptide reconstitution calculator instead.
Frequently asked questions
How do I calculate my HCG dose?
Divide the vial's IU by the millilitres of bacteriostatic water you added to get IU per mL. Divide that by 100 to get IU per unit on a U-100 syringe. Then divide your prescribed dose by IU per unit. Example: 5,000 IU in 2 mL is 2,500 IU/mL, which is 25 IU per unit, so 500 IU is 20 units.
How do you mix a 5000 IU vial of HCG?
Add bacteriostatic water to the powder vial, most commonly 1 to 5 mL. With 5,000 IU in 2 mL the concentration is 2,500 IU/mL, so a 500 IU dose is 0.2 mL, which is 20 units on a U-100 syringe. Inject the water down the vial wall and swirl rather than shake, because HCG is a fragile glycoprotein.
How much bacteriostatic water should I add to a 5,000 IU vial?
There is no single correct volume, because the water only sets concentration. Common choices are 1, 2, 3 or 5 mL. More water gives larger, easier-to-measure syringe volumes, which reduces measurement error on small doses. Whatever you choose, keep it constant for that vial and write it on the label.
How many units is 250 IU of HCG?
It depends entirely on concentration. With 5,000 IU in 5 mL (1,000 IU/mL) it is 25 units. With the same vial in 2 mL (2,500 IU/mL) it is 10 units. Recalculate whenever your water volume changes.
How long does reconstituted HCG last?
Refrigerated at 2-8 °C, manufacturer labeling for common products states 30 days when bacteriostatic water was used. With plain sterile water there is no preservative, so it is single-use. Follow your product's labeling.
Is a HCG dosage calculator the same as a reconstitution calculator?
They are two directions through the same arithmetic. A reconstitution or mixing calculator starts from the vial and water to give you a concentration; a dosage calculator starts from your prescribed dose to give you units to draw. This page does both, because the concentration has to exist before the dose figure means anything.
Can I use insulin syringe units for HCG?
Yes, and it is the usual approach. HCG doses are small in volume, and a U-100 insulin syringe is graduated in units where 100 units = 1 mL. Measuring 0.1-0.5 mL is far more accurate there than on a 3 mL syringe. Every unit figure on this page assumes U-100.
How do I convert HCG IU to mL?
Divide your dose in IU by the vial's concentration in IU/mL. A 500 IU dose from a vial mixed to 2,500 IU/mL is 500 ÷ 2,500 = 0.2 mL, which is 20 units on a U-100 syringe. The concentration depends entirely on how much water you added at mixing time, so check the label you wrote on the vial.
Can I use a peptide calculator for HCG?
Usually not directly. Peptide reconstitution calculators expect vial strength in mg or mcg, but HCG is measured in IU, a biological activity unit with no fixed weight conversion. Use an IU-native HCG calculator like this one; for mg-based peptides such as BPC-157 or semaglutide, use our peptide reconstitution calculator.