Calculator overview
What does a hCG reconstitution calculator do?
An hCG reconstitution calculator converts the strength of a vial into a measurable liquid volume. It shows how many international units are present in each millilitre after the powder has been mixed with the stated volume of diluent.
Once the concentration is known, the calculator can work out how many millilitres correspond to the dose entered and how that volume translates to the markings on a U-100 insulin syringe.
This is a mathematical conversion tool. It does not prescribe hCG, recommend a treatment protocol or confirm that a preparation method is suitable for you.
Treatment information
hCG and testosterone replacement therapy
Some people receiving testosterone replacement therapy may be prescribed hCG as part of an individual treatment plan. The reasons for prescribing it, the dose used and the monitoring required depend on the patient and must be decided by a qualified clinician.
Within hormone care, hCG may be discussed when fertility, testicular function or future family planning is relevant. It is not automatically required for every person taking testosterone.
This calculator is a general educational tool and does not replace advice from your prescriber, clinic, pharmacist or medication manufacturer.
The maths
How hCG reconstitution is calculated
The calculator first divides the total number of IU in the vial by the number of millilitres added.
It then divides the entered dose by that concentration to find the liquid volume required.
A U-100 insulin syringe is marked as 100 units per millilitre, so the calculated volume is multiplied by 100 to display the corresponding syringe marking.
Worked example
Example hCG reconstitution calculation
The following example demonstrates the calculation only. It is not a dosing recommendation.
In this example, the concentration is 2,500 IU per mL. Dividing 250 IU by 2,500 IU/mL gives a volume of 0.10 mL, which corresponds to 10 units on a U-100 syringe.
Understanding the result
IU, millilitres and insulin syringe units
These measurements describe different things:
- IU describes the biological activity or stated strength of the medication.
- mL describes the volume of liquid being drawn.
- U-100 syringe units are volume markings where 100 marked units equal 1 mL.
A syringe marking is not the same as an hCG dose in IU. The amount represented by each syringe marking changes whenever the concentration changes.
Preparation
Which diluent volume should you enter?
Enter the exact number of millilitres used to prepare your vial. Do not select a volume simply because it creates a convenient syringe marking.
The correct diluent and preparation method depend on the specific product supplied. Follow the instructions from your prescribing clinic, pharmacy or manufacturer, because storage and use after mixing can differ between products.
If the supplied information does not match the options shown, use the custom-volume field or ask a pharmacist to confirm the correct preparation before proceeding.
Safe use
Important limitations of this calculator
- The result is only as accurate as the values entered.
- The tool does not check your prescription or medication label.
- Displayed syringe units are rounded to the nearest whole unit.
- Different syringes may use different graduations.
- The tool does not provide injection or sterile-technique training.
- Medication storage instructions vary by product and diluent.
A clinician or pharmacist should review any calculation you are uncertain about. Never change your prescribed dose based on the output of an online calculator.