Peptide calculator
Enter what's in the vial, the water you added, and your dose. PepExact gives you the exact units on the syringe — and shows the math.
Your draw
10 units
on a U-100 insulin syringe · 0.1 mL
Concentration
2.5 mg/mL
2,500 mcg/mL
Volume per dose
0.1 mL
Doses in this vial
20
at 250 mcg each
Show the math
- 1. Concentration: 5 mg ÷ 2 mL = 2.5 mg/mL (2,500 mcg/mL)
- 2. Volume for one dose: 250 mcg ÷ 2,500 mcg/mL = 0.1 mL
- 3. Syringe units (U-100): 0.1 mL × 100 units/mL = 10 units
- 4. Doses in the vial: 5,000 mcg ÷ 250 mcg = 20 full doses
Keep this vial on your phone
PepExact for iPhone saves your vial, renders the syringe, and counts doses left — even offline.
How the calculation works
Every peptide dose calculation is the same three steps of arithmetic, whatever the compound:
- Concentration — vial contents (mg) ÷ water added (mL) = mg per mL.
- Volume — your dose ÷ concentration = mL to draw.
- Units — mL × 100 = marks on a U-100 insulin syringe.
The most common error is a units mix-up: 1 mg is 1,000 mcg, so confusing the two shifts a dose by a factor of a thousand. PepExact keeps mg and mcg explicit at every step.
Common questions
How does a peptide calculator work?
It is three steps of arithmetic. First, concentration: the mg in the vial divided by the mL of water added. Second, volume: your dose divided by that concentration. Third, syringe units: volume in mL multiplied by 100, because a U-100 insulin syringe holds 100 units per mL.
How many units is my dose?
It depends entirely on how much water was added to the vial. Example: a 5 mg vial reconstituted with 2 mL of water is 2.5 mg/mL. A 250 mcg dose is then 0.1 mL, which is 10 units on a U-100 syringe. The same dose from the same vial with 1 mL of water would be 5 units.
What syringe do the units refer to?
U-100 insulin syringes, the most common type. U-100 means 100 units per mL, so 1 unit is always 0.01 mL — whether the syringe is a 0.3 mL, 0.5 mL, or 1.0 mL size.
Why do different peptide calculators give different answers?
Usually rounding, unit confusion (mg vs mcg), or assumptions about syringe type. PepExact shows every step of the working so you can verify the number rather than trust it blindly.
PepExact is a measurement tool, not medical advice. It never suggests what or how much to take — it only does the arithmetic on numbers you already have.