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TRT Dose Calculator

A weekly total divided by the number of injections gives what each one comes to; the concentration printed on the vial turns that into a volume and a mark on a syringe. The concentration is asked for rather than assumed — testosterone cypionate is labelled at both 100 and 200 mg/mL, so assuming one would put a reader holding the other out by a factor of two.

Last reviewed: September 21, 2026

A weekly total divided by the number of injections gives what each one comes to; the concentration printed on the vial turns that into a volume.

Read it off your own vial. The chips are the strengths Prof. Peptide has read on a label — cypionate is sold at both 100 and 200 mg/mL, so assuming one would put a reader holding the other out by a factor of two.

How the arithmetic works

  • Each injection (mg) = weekly total (mg) ÷ injections per week
  • Volume each time (mL) = each injection (mg) ÷ concentration (mg/mL)
  • Syringe units = volume (mL) × 100, on a U-100 insulin syringe

Unlike a lyophilized peptide, an oil-based testosterone ester arrives already at a fixed concentration — there is no water volume to add, and no vial-plus-water step. The concentration is the number printed on the vial, entered directly.

Worked example

A 100 mg weekly total, split across 2 injections, at 200 mg/mL:

Each injection100 mg ÷ 2 = 50 mg
Volume each time50 mg ÷ 200 mg/mL = 0.25 mL
Syringe units0.25 mL × 100 = 25 units
Used per week100 mg ÷ 200 mg/mL = 0.5 mL

Enter the same three numbers into the calculator above and it returns the same figures.

What changes the answer

  • Concentration. The same 50 mg injection is 0.25 mL at 200 mg/mL but 0.5 mL — twice the volume — at 100 mg/mL. This is the single most consequential input on the page, since both strengths are genuinely sold.
  • Injections per week. More injections divide the same weekly total into smaller individual amounts; fewer injections make each one larger. The weekly total itself is unaffected.
  • Syringe calibration. Every unit figure assumes a U-100 syringe (100 units = 1 mL) — see the syringes and injection guide. The unit mark measures the volume drawn; it reads the same whether that volume is an oil-based ester or a reconstituted aqueous solution.

FAQ

How do I split a weekly testosterone dose into two injections?
Divide the weekly total by the number of injections: 100 mg ÷ 2 = 50 mg each. The volume that comes to depends on the concentration printed on the vial — at 200 mg/mL, 50 mg is 0.25 mL (25 units on a U-100 syringe); at 100 mg/mL, the same 50 mg is 0.5 mL (50 units).
trt dose calculator weekly
This page's calculator takes a weekly total in mg, a number of injections per week, and the concentration printed on your vial, and returns what each injection comes to in mg, mL and syringe units, plus the total volume used per week.
What concentration is testosterone cypionate?
Cypionate is labelled at both 100 mg/mL and 200 mg/mL, depending on the product — Prof. Peptide has read both strengths directly off FDA prescribing information. Enanthate is labelled at 200 mg/mL. The concentration on this page is a field you fill in from your own vial, not a value it assumes, since assuming one would put a reader holding the other strength out by a factor of two.
Does the number of injections per week change the total dose?
No. Splitting 100 mg/week into two injections or four injections both total 100 mg/week — the total is unchanged, only how it's divided and how often it's administered.

For a single dose rather than a weekly split, see the TRT injection calculator. To calculate free and bioavailable testosterone from a lab panel, see the free testosterone calculator.