Dose & syringe converter

How this calculator works

Draw volume in milliliters equals the prescribed dose in milligrams divided by the vial's concentration in milligrams per milliliter. A U-100 insulin syringe is marked in units, where 100 units equal 1 milliliter, so the unit marking is the draw volume multiplied by 100.

If you enter a weekly total dose along with the number of injections per week, this tool also divides that weekly total evenly across injections to show the per-injection dose, then converts that figure the same way.

Reading your vial label

Testosterone cypionate and enanthate are most commonly dispensed at 100 mg/mL or 200 mg/mL, though compounding pharmacies can prepare other concentrations. Always read the concentration printed on your specific vial rather than assuming a standard strength.

Choosing a syringe size

U-100 insulin syringes commonly come in 0.3 mL (30-unit), 0.5 mL (50-unit), and 1 mL (100-unit) sizes. A syringe close in size to your actual draw volume reads more precisely than a much larger one, since the same small volume spans more of the scale.

Needle gauge and length are set by your prescriber or pharmacy based on your injection site and formulation, not something this tool determines. Follow the specific needle your prescriber recommends rather than guessing from general references.

Why this matters

A misread concentration is one of the most common sources of dosing error in self- administered testosterone therapy, since 100 mg/mL and 200 mg/mL vials can look similar. Checking the arithmetic against your own vial label before drawing a dose is a simple way to catch that kind of mistake.

Frequently asked questions

How do I convert a testosterone dose into a syringe draw volume?

Divide the prescribed dose in milligrams by the vial's concentration in milligrams per milliliter. The result is the draw volume in milliliters, which this tool also converts to U-100 insulin syringe markings by multiplying by 100.

What does a U-100 marking mean?

A U-100 insulin syringe is marked in units where 100 units equals 1 milliliter. Many TRT patients draw testosterone with an insulin syringe because the markings allow finer, more precise volume measurement than a standard 3 mL syringe.

Can this tool tell me how much testosterone to take?

No. This tool only converts a dose your prescriber has already set into a draw volume. It does not suggest a starting dose, a dose change, or an injection frequency. Any dose adjustment should come from the clinician managing your treatment.

Why do vial concentrations vary between 100 mg/mL and 200 mg/mL?

Compounding and manufacturing differences mean testosterone cypionate and enanthate are commonly dispensed at either 100 mg/mL or 200 mg/mL. Always check the vial label rather than assuming a concentration.