The Peptide Calculator answers one question: how many units do I draw on the syringe for my dose? It does the arithmetic so you do not have to. It does not tell you what dose is right for you.
The three numbers it needs
- Peptide in the vial (mg): the amount printed on the label, such as 5 mg or 10 mg. Tap a preset or type your own.
- Water added (mL): how much bacteriostatic water you put in, or plan to put in.
- Your dose: in mcg or mg. Use the mcg/mg switch to match how your dose is written.
You can also choose your syringe size (30, 50 or 100 units). The picture and warnings adjust to match.
Reading the result
- Units to draw: the big number. This is the mark on a U-100 insulin syringe.
- Syringe picture: shows where the liquid should reach.
- Volume: the same amount in mL.
- Concentration: how much peptide is in each mL of your mixed vial. Write this on the vial label.
- Doses per vial: how many doses of that size the vial holds.
Worked examples
| Vial | Water | Dose | Draw | Doses per vial |
|---|---|---|---|---|
| 5 mg | 2 mL | 250 mcg | 10 units | 20 |
| 5 mg | 2 mL | 0.25 mg | 10 units | 20 |
| 10 mg | 2 mL | 2.5 mg | 50 units | 4 |
| 10 mg | 1 mL | 100 mcg | 1 unit | 100 |
The last row shows why water matters: a 1-unit dose is very hard to measure. Mixing that vial with 2 mL instead makes the same dose 2 units, and 3 mL makes it 3 units. The calculator warns you when a dose is too small to measure well or too large for your syringe.
The math, if you want it
- Concentration = mg in vial ÷ mL of water. (5 mg ÷ 2 mL = 2.5 mg/mL, which is 2,500 mcg/mL.)
- Volume = dose ÷ concentration. (250 mcg ÷ 2,500 mcg/mL = 0.1 mL.)
- Units = mL × 100. (0.1 mL × 100 = 10 units.)
Tap Show the math under any result to see these steps with your own numbers.
Handy features
- Copy link: saves your numbers in a link you can bookmark or send.
- Print mix card: a small card with your vial, water, concentration and units to keep with your supplies.
- Calculators on peptide pages: each encyclopedia entry has a calculator pre-filled with common vial sizes for that peptide.
Products measured in IU
A few products are labeled in international units (IU) instead of mg. Their encyclopedia entries explain how to enter them. For example, HGH is converted by dividing IU by 3 to get mg, and HCG can be entered with IU in place of mcg.
Common mistakes
- Mixing up mcg and mg. 1 mg = 1,000 mcg. A 250 mcg dose is 0.25 mg, not 250 mg.
- Copying someone else’s “units.” Units only match if your vial size and water amount match theirs exactly.
- Using the wrong syringe. All results assume U-100 insulin syringes. U-40 syringes use a different scale.
- Forgetting what you mixed. Label every vial with the date and concentration.