TRT Dosage Calculator

The TRT dosage calculator takes four inputs and returns the only number you need at the point of drawing.

Decide whether you are working from a weekly total or a per-injection amount. Enter the milligrams. Select the concentration printed on the vial. Choose how many times a week you inject.

Back comes the volume per injection in ml, and the same volume as units on a U-100 syringe.

TRT Dosage Quick-Reference Table

The table below runs the standard dose-to-volume conversion across the three concentrations you will actually encounter: 100 mg/ml, 200 mg/ml, and 250 mg/ml.

How TRT Dose Calculations Work

Underneath everything, a TRT dosage calculator is a dose-to-volume converter and one division:

ml per injection = dose (mg) / concentration (mg/ml)

60 mg prescribed per injection from a 200 mg/ml vial is 0.3 ml.

On a 1 ml U-100 insulin syringe, 1 ml is 100 units, so 0.3 ml reads as 30 units, 0.50 ml as 50, and 0.75 ml as 75. Those markings measure volume, never dose. The same 30 units from a different vial strength is a different amount of testosterone, which is why the syringe type and the vial concentration both get checked before you draw.

A worked case, start to finish:

1. Total weekly dose: 120 mg
2. Concentration per vial: 200 mg/ml
3. Frequency of administration: 2 injections per week

120 mg across two injections is 60 mg each. 60 mg divided by 200 mg/ml is 0.30 ml. That is 30 units on a U-100 1 mL syringe.

Cypionate vs Enanthate vs Propionate

Esters come up constantly in TRT math, usually with more anxiety than they deserve.

Every ester delivers testosterone, and the dose-to-volume conversion does not change between them. Cypionate, enanthate or propionate, the calculator divides milligrams by mg/ml the same way.

What does change is the schedule:

Shorter esters clear faster, which is why they tend to be injected more often: fewer days between shots means smaller peaks and troughs. The volume calculation is identical regardless.

Splitting Your Weekly TRT Dose

One injection a week means the whole weekly amount converts at once. Simplest math, largest single volume.

Two injections means halving the weekly milligrams before converting to ml, not after. This is the step people skip, and it is the reason most users come to a testosterone dose calculator: they know the weekly figure and need the per-shot draw.

Three injections means dividing by three first. That usually produces an awkward decimal, so the tool rounds to something you can actually read on a barrel.

All of the following assume a 200 mg/ml vial:

Why 200 mg/ml and 250 mg/ml Vials Are Not Interchangeable

Nothing in TRT dosing catches people out more reliably than a refill at a different concentration. The prescription is unchanged, the label looks familiar, and the volume you have drawn for months is now wrong.

Same 100 mg dose, three vials:

1. 100 mg/ml: 1.0 ml, which is 100 units. A full U-100 barrel.
2. 200 mg/ml: 0.5 ml, which is 50 units.
3. 250 mg/ml: 0.4 ml, which is 40 units.

Keep drawing 50 units after moving from a 200 mg/ml vial to a 250 mg/ml vial and you are taking 125 mg instead of 100, a 25% increase that no symptom will announce and only bloodwork will find.

What makes it easy to miss:

1. Nothing about the injection feels different. The volume difference between 40 and 50 units is a couple of millimetres of barrel.
2. Concentration is the smallest print on the label. The compound name and the volume are what the eye goes to.
3. People remember units, not milligrams. Months of drawing to the same mark turns the mark into the dose, and the mark is not the dose.

Re-run the calculator every time a vial changes, even when the prescription has not. It takes ten seconds and it is the only step that catches this.

Safety Notes Before You Inject

The output is only as good as the three numbers going in. Confirm the dose in mg, the concentration in mg/ml and the injection frequency before drawing, because correct math on a wrong input is still a wrong volume in the syringe.

This calculator supports a prescribed plan; it does not modify one. Monitoring matters once testosterone therapy has started: the Endocrine Society recommends checking hematocrit at baseline, at 3-6 months, and annually thereafter, with prostate monitoring where appropriate.

This page is not medical advice. It does not diagnose low testosterone, suggest a starting dose, or establish whether TRT is appropriate for you. Those are decisions for a qualified clinician.