How to Use This Calculator
Enter the vial size in mg, the water you added in mL, the dose per injection in mcg, the syringe size, how many injections a week and the cycle length in weeks. Click Calculate to see the doses per vial, how many days a vial lasts, the units to draw, the total injections, the vials to order and how many doses are left over at the end.
Why This Matters for Ordering, Not Just Dosing
Running out of a compound mid-cycle is one of the more common planning mistakes, usually because vial yield was estimated roughly rather than calculated against the actual dose and frequency. A vial that looks like it should last a set number of weeks based on a round-number guess can come up short once the real dose and injection frequency are accounted for exactly, particularly for protocols with a dose that changes partway through.
Budgeting the Full Order
Once the vial count is known, the Peptide Cycle Cost Estimator turns that number into a full projected budget for the cycle, consumables included. If the protocol includes a planned dose change partway through, the Peptide Protocol Builder lays out that full multi-phase timeline in one place.
Who Should Use This
Researchers planning how many vials to order for a cycle; anyone checking how long one vial lasts at a given dose and frequency.
What This Calculator Does
The Peptide Vial Yield Calculator works out how many doses one vial gives, how many days it lasts at your injection frequency, and the draw per injection. For a full cycle it also calculates total injections, total compound, the number of vials to buy and the doses left over in the last vial.
Formula Used
Doses per vial = FLOOR(Vial size (mg) × 1,000 ÷ Dose (mcg))Days per vial = Doses per vial ÷ Injections per week × 7Units per injection = Dose ÷ Concentration × 100 (U-100)Total injections = Cycle weeks × Injections per weekVials needed = CEILING(Total injections ÷ Doses per vial)Example Calculation
Limitations
Assumes no reconstitution or draw loss and the same dose throughout. Many reconstituted peptides should be used within a limited period (often 28 to 30 days refrigerated), which can be shorter than the calculated days per vial.
Frequently Asked Questions
How long does a peptide vial last?
Doses per vial = vial size in mg × 1,000 ÷ dose in mcg. Days per vial = doses per vial ÷ injections per week × 7. For example, a 10 mg vial at 500 mcg once a day gives 20 doses, so it lasts 20 days.
How many vials do I need for a cycle?
Multiply the cycle length in weeks by injections per week to get total injections, then divide by the doses per vial and round up. For example, a 12-week cycle at once a day is 84 injections, and with 20 doses per vial that is 4.2, so 5 vials.