How TRT Dose Calculator Works

A short guide to the inputs, formulas, and worked example so you know exactly what the calculator does.

How it works

Four short steps. The math is pure arithmetic - it does not model half-life, peak/trough changes, or individual medical factors.

Choose whether you think in mg/week or in the real amount you draw into the syringe.

Read the vial concentration in mg/mL - for example 100, 200, or 250 mg/mL.

Daily, every other day, 2x weekly, 3x weekly, or a custom interval.

You get mg per injection, mL volume, U-100 units, weekly dose, schedule, and vial usage.

Worked example

You enter

You get

In this example each injection is 0.25 mL - the 25-unit mark on a U-100 syringe, twice weekly.

Every result comes from the formulas below. They run in the browser, so what you see in the calculator is the actual math.

doses_per_week = 7 / interval_days

mg_per_injection = weekly_mg / doses_per_week

mL_per_injection = mg_per_injection / concentration_mg_per_mL

weekly_mL = weekly_mg / concentration_mg_per_mL

units_per_injection = mL_per_injection × 100

compound_mg = compound_concentration × injection_mL

doses_per_vial = floor(vial_volume_mL / mL_per_injection)

days_of_supply = doses_per_vial × interval_days

Context

mg vs mL: mg is the amount of active compound, while mL is the physical volume you draw into the syringe.
Concentration: At 250 mg/mL, each 1 mL contains 250 mg. That means 0.10 mL contains 25 mg.
Every other day: EOD is calculated as an average of 3.5 injections weekly because calendar weeks alternate between 4 and 3 injections.
Blends: In Blend mode, each compound is calculated from its own concentration, while the syringe is based on total mL.

Educational use only - not medical advice. Verify every dose with a licensed clinician. Read the full disclaimer.