TRT protocols are usually planned around a weekly total (e.g. 100–200mg/week of testosterone cypionate or enanthate), then split across 1–7 injections. Enter your weekly target and frequency to get the per-injection dose, draw volume and syringe units. Want the half-life behind why frequency matters? See the Testosterone Half-Life Calculator.
Weekly-total calculator
A one-off calculation — nothing here is saved or sent anywhere.
Common commercial concentrations: testosterone cypionate and enanthate are frequently compounded or dispensed at 100mg/mL or 200mg/mL — check your own vial label, since compounding pharmacies vary.
How to Use This Calculator
Four inputs, matching how most TRT protocols are actually planned — around a weekly total, not a single injection.
Enter your weekly targetMost TRT protocols are described as a weekly total in mg (e.g. "150mg/week"), even when injections happen more or less often than once a week.
Choose your injection frequencySplitting the same weekly total across more, smaller injections is a common strategy some protocols use to reduce the peak-to-trough swing between doses — see the methodology section below for why.
Enter your concentrationCheck your vial or prescription label — common testosterone cypionate/enanthate concentrations are 100mg/mL and 200mg/mL, but compounded products vary.
Read your per-injection numbersThe result shows the mg, mL, and syringe units for a single injection at your chosen frequency.
How the Math Works
Simple division and the same reconstitution math used throughout this site — the frequency logic reflects testosterone ester pharmacokinetics published in FDA labeling.
Per-injection dose. Per-injection mg = weekly target (mg) ÷ injections per week. Splitting a weekly total more finely reduces the single largest injection amount but increases how often you inject. Basic arithmetic division.
Why frequency is discussed at all. Testosterone cypionate and enanthate are long-acting esters with elimination half-lives in the range of roughly 4.5–8 days depending on the specific ester and formulation, so blood levels naturally rise after each injection and fall until the next one — more frequent, smaller injections produce a flatter overall curve for the same weekly total. FDA prescribing information for testosterone cypionate and enanthate injectable products; published pharmacokinetic literature on testosterone ester half-lives.
Draw volume and syringe units. Draw volume (mL) = per-injection dose (mg) ÷ concentration (mg/mL). Syringe units = draw volume (mL) × the syringe's units-per-mL rating (100 for U-100, 40 for U-40). Standard pharmaceutical dosage calculation; ISO 7864 syringe graduation standards.
Estimate only — not medical advice. This tool performs arithmetic based on numbers you enter — it does not recommend a weekly target, a frequency, or a concentration for you. TRT dosing should be established and monitored by a licensed clinician based on your labs, symptoms, and response to treatment. Individual variation in how testosterone is metabolized is significant.
Frequently Asked Questions
Why do some TRT protocols split the weekly dose into more frequent injections?
Because testosterone esters clear the body gradually rather than instantly, injecting the full weekly amount all at once produces a higher peak right after injection and a lower trough right before the next one. Some prescribers and patients prefer more frequent, smaller injections to smooth out that peak-to-trough swing — though the clinical significance of doing so varies by individual and is a decision to make with your prescriber, not this calculator.
What's a typical TRT starting dose?
This varies enormously by individual, lab values, and prescriber protocol — there is no single "typical" dose this tool can responsibly suggest. Common ranges cited in clinical literature span roughly 50–200mg/week of testosterone cypionate or enanthate, but your actual target should come from your prescriber based on your labs and goals.
What concentration is my testosterone?
Check your vial label or pharmacy printout directly — concentrations for compounded and commercial testosterone cypionate/enanthate commonly run 100mg/mL or 200mg/mL, but this varies by pharmacy and product. Never assume a concentration; confirm it.
Does injection frequency change the total weekly dose?
No — this calculator keeps your weekly total fixed and only changes how it's divided across injections. Changing frequency changes the size of each individual injection, not the cumulative weekly amount.
Is testosterone cypionate the same half-life as enanthate?
They're close but not identical — cypionate is commonly cited around 8 days and enanthate somewhat shorter, though published figures vary by study and formulation. See the Testosterone Half-Life Calculator for a compound-specific estimate.
Can I use this for testosterone propionate or undecanoate?
The dose-splitting math works for any ester, but propionate and undecanoate have very different half-lives (propionate is much shorter, undecanoate much longer) and are typically dosed on completely different schedules — every other day for propionate, every 8–12 weeks for undecanoate. Adjust your frequency selection accordingly, or consult your prescriber's specific protocol.
Why is my per-injection mg number not a round figure?
Weekly totals don't always divide evenly across a chosen frequency. A non-round per-injection amount (like 42.86mg) is mathematically correct — whether to round up, down, or adjust your weekly target to a cleaner number is worth discussing with your prescriber.
Does this account for how testosterone converts to estrogen or other metabolites?
No — this is a dose and volume calculator only. It does not model hormone conversion, individual metabolism, or any physiological response. Bloodwork and clinical monitoring are how those factors get evaluated.
Is this the same as the Reconstitution Calculator?
It uses the same underlying math, but this tool is built around the weekly-total framing TRT protocols typically use, rather than a single vial-and-dose entry. For blends, non-hormone peptides, or a different calculation direction, use the full Reconstitution Calculator.
Does this tool save my numbers anywhere?
No — everything runs in your browser and nothing is stored or transmitted. To track your actual injection history and site rotation over time, see the full Peptide Plug app.
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