Peptide calculator
First time? You're in the right place. Answer the questions with what's printed on your vial and syringe, and we'll show you exactly where to draw to, with the working shown.
It's printed on the vial label, for example 10mg. This is the powder before any water goes in.
Where is it on the label?
The amount is the big figure on the label, in mg. Ignore the volume of water or the batch number.
Use the number and unit exactly as you were given it. Doses under 1 mg are usually written in mcg (micrograms). 1 mg is 1,000 mcg.
Bacteriostatic water, in mL. If you're not sure, check what you wrote down when you mixed it.
Look at the biggest number printed on the side of the syringe.
Not sure? See the three sizes
All three are U-100 insulin syringes: 100 units is 1 mL. The top mark tells you which one you have. A 1 mL syringe has a line every 2 units, so count carefully.
To work out a peptide dose, divide the mg in the vial by the mL of water you added to get the strength. Divide your dose by the strength to get mL, then multiply by 100 for units on a U-100 insulin syringe. Example: 10 mg in 2 mL is 5 mg/mL, so 250 mcg is 0.05 mL, or 5 units.
Every step is shown
Open "Show the maths" and you can check each line yourself, or show it to someone you trust.
We catch the common slips
Mixing up mg and mcg, or picking the wrong syringe, are the usual mistakes. We flag both before you draw.
Nothing to sell you
No shop, no seller links, no account. Your numbers stay on your device.
Worked examples
Common vial and water combinations for a 250 mcg dose, drawn on a 1 mL (100 unit) syringe. Generated by the calculator's own tested code.
| Vial | Water | Strength | 250 mcg is | Doses per vial |
|---|---|---|---|---|
| 5 mg | 1 mL | 5 mg/mL | 5 units (0.05 mL) | 20 |
| 5 mg | 2 mL | 2.5 mg/mL | 10 units (0.1 mL) | 20 |
| 5 mg | 3 mL | 1.67 mg/mL | 15 units (0.15 mL) | 20 |
| 10 mg | 1 mL | 10 mg/mL | 2.5 units (0.025 mL) | 40 |
| 10 mg | 2 mL | 5 mg/mL | 5 units (0.05 mL) | 40 |
| 10 mg | 3 mL | 3.33 mg/mL | 7.5 units (0.075 mL) | 40 |
The two mistakes we check for
mg and mcg mixed up. 1 mg is 1,000 mcg. Typing 250 mg when you meant 250 mcg asks for a thousand times the amount, so the calculator stops you when a dose is bigger than the whole vial.
Units and mL mixed up. The FDA has received reports of people drawing ten times their intended dose by confusing units with mL on a syringe (FDA alert, July 2024). That's why every answer here is shown as units, as mL and as a drawing of the syringe.