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Testosterone Vial Calculator

Enter your vial size, concentration, and weekly dose, find out exactly how many weeks it will last and how much is lost to dead space.

Vial longevity

How long your vial lasts

Injections per vial, weeks of supply, and dead-space waste.

mL
mg/mL
mg
mL

~0.04 mL for standard needles, ~0.005 mL for fixed-needle (low dead space)

$

Your vial will last approximately

12weeks

24 injections from a 10 mL vial

Per injection
0.375mL
Total injections
24
Lost to dead space
192mg
(9.6%)

so a new vial arrives before this one's empty

Runs out around
Dec 6, 2026
Reorder by
Nov 29, 2026
Keep your vials in Regimen and get a heads-up before they run out.Add to Regimen

This calculator is for informational purposes only, so always double-check your result with a healthcare provider. We assume no liability for dosing errors.

The tool

How it works, what it tells you, what it doesn't.

The vial longevity calculator tells you how many weeks your testosterone or hormone vial will last based on your current protocol. Enter vial size (mL), concentration (mg/mL), weekly dose (mg), and injection frequency. The calculator accounts for needle dead space, the small amount of medication trapped in the needle hub after each injection, and shows you how much medication is being wasted. Add the vial cost for a weekly cost breakdown.

How to use it

How to Use This Calculator

  1. 01

    Enter your vial size

    The total mL volume of your testosterone vial (1 mL or 10 mL)

  2. 02

    Enter concentration

    The mg/mL printed on your vial label (usually 200 mg/mL)

  3. 03

    Enter your weekly dose

    Your total prescribed dose per week in mg

  4. 04

    Set injection frequency

    How many times per week you inject (1x, 2x, 3x, or daily)

How long does a testosterone vial last?

VialTotal testosterone100 mg/wk150 mg/wk200 mg/wk250 mg/wk
10 mL2,000 mg~20 wks~13 wks~10 wks~8 wks
5 mL1,000 mg~10 wks~6.5 wks~5 wks~4 wks
3 mL600 mg~6 wks~4 wks~3 wks~2.5 wks

Assumes a 200 mg/mL vial (most common). For other concentrations, use the calculator above.

Data Sources

This tool uses dosing information from official prescribing information:

  • USP Multi-Dose Vial Guidelines - 28-day beyond-use date for multi-dose vials per USP <797>
  • Dead Space Research - Standard needle dead space ~0.04 mL; LDS needles ~0.003 mL

Get the app

Track Your TRT Protocol

Regimen logs every injection, tracks vial usage, and reminds you when to reorder. Free for one compound.

  • Built-in dose calculators
  • Smart injection reminders
  • Log levels, symptoms, and progress
  • Private, secure health data
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Free to download. Free for your first compound.

Regimen app Today view with doses and estimated levels

Questions

Vial Longevity Q&A

How long does a 10 mL testosterone vial last?
A 10 mL vial of 200 mg/mL testosterone holds 2,000 mg total. At 100 mg/week it lasts about 20 weeks. At 150 mg/week, about 13 weeks. At 200 mg/week, about 10 weeks. Dead space from standard needles shortens these numbers by roughly 8% at 200 mg/week and up to about 16% at 100 mg/week, because every injection loses the same 0.04 mL and a smaller dose means more injections per vial. Use the calculator above for your exact dose, frequency, and needle type.

What is syringe dead space and how much testosterone does it waste?
Dead space is the small amount of liquid trapped in the needle hub and syringe tip after injection. A standard needle wastes about 0.04 mL per injection. On a 10 mL vial that is roughly 8% of your medication at 200 mg/week and about 16% at 100 mg/week, since the smaller dose takes twice as many injections to finish the vial. Fixed-needle (low dead space) syringes, where the needle is bonded into the barrel rather than screwed on, strand close to none.

Should I use low dead space needles for TRT?
If you inject frequently (2+ times per week), LDS needles can save you hundreds of mg over the life of a vial. They're especially worth it for expensive medications or smaller 1 mL vials. They cost slightly more but pay for themselves in saved medication.

How many injections can I get from a 1 mL testosterone vial?
With a 200 mg/mL vial and 100 mg per injection (0.5 mL), you'll get 2 injections. With dead space, you might only get 1 full injection and a partial second. This is why many people prefer 10 mL multi-dose vials.

Does testosterone expire once the vial is opened?
USP guidelines say multi-dose vials should be discarded 28 days after first puncture. In practice, many TRT clinics allow longer use if stored properly (room temperature, away from light). Check with your provider and watch for cloudiness or particles.

How do I calculate my cost per week for TRT?
Divide the cost of your vial by the number of weeks it lasts. Enter your vial cost in the optional field above to see this automatically. Don't forget to factor in syringes, needles, and alcohol swabs.

When should I reorder my vial?
Work out the day your current vial runs out (doses left × days between doses), then order a few days before that so the new one arrives in time. The calculator shows both dates above - pick a 3, 7, or 14-day buffer based on your typical shipping time.

Do low dead space syringes actually save medication?
Yes, and it adds up. Dead space is the medication stranded in the needle hub after you inject. A standard detachable needle holds roughly 0.04 mL there. Fixed-needle insulin syringes, where the needle is bonded into the barrel rather than screwed on, strand close to none. Note that slip-tip and Luer-lock describe how the needle attaches, not dead space: a slip-tip syringe still takes a detachable needle.

Can I mix vials?
You can start a new vial once the previous one is empty. Drawing from two vials into one injection to use up a remainder is an advanced move, so check with your pharmacist or prescriber before doing it.

How does injection frequency affect vial longevity?
Every injection loses some medication to dead space, so injecting more often wastes more per week. The calculator accounts for this. Switching to fixed-needle syringes largely cancels it out.

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