Peptide calculator
Vial milligrams, water millilitres and syringe units, converted with the arithmetic shown. Works for single peptides and blend vials, on U-100 and U-40 syringes.
Concentration
5mg/mL
Enter an amount to see the syringe reading.
What each reading holds
| Units (U-100) | mL | Holds |
|---|---|---|
| 10 | 0.1 | 500 mcg |
| 25 | 0.25 | 1.25 mg |
| 50 | 0.5 | 2.5 mg |
| 100 | 1 | 5 mg |
Work backwards: how much water?
Pick how many units you want your amount to read, and this gives the water volume that produces that concentration.
Enter the vial amount and the amount to measure first.
Math only. Check every number against your vial label.
By [Author name]. Licensed pharmacist review: pending. Last updated .
Calculators by compound
Same math, set up for each compound's usual vial sizes, with a concentration table, handling notes and regulatory status.
- Retatrutide5, 10, 15, 20, 30 mg vialsInvestigational, not approved
- Tirzepatide5, 10, 15, 20, 30, 60 mg vialsFDA-approved drug exists
- Semaglutide2, 3, 5, 10 mg vialsFDA-approved drug exists
- BPC-1575, 10 mg vialsNot an approved drug
- TB-5002, 5, 10 mg vialsNot an approved drug
- BPC-157 + TB-500 blendBlend: BPC-157 + TB-500Not an approved drug
- GHK-Cu50, 100 mg vialsNot an approved drug
- GLOW and KLOW blendsBlend: GHK-Cu + BPC-157 + TB-500 + KPVNot an approved drug
- CJC-1295 / IpamorelinBlend: CJC-1295 + IpamorelinNot an approved drug
- MOTS-c5, 10, 40 mg vialsNot an approved drug
- NAD+100, 500, 1000 mg vialsNot an approved drug
- Tesamorelin2, 5, 10 mg vialsFDA-approved drug exists
- Sermorelin2, 5, 10 mg vialsApproved product discontinued
How the math works
A lyophilized vial holds a fixed mass of powder. Adding water turns it into a solution with a concentration, and a syringe measures volume. Every answer on this site comes from those three facts:
- Concentration = vial mg ÷ water mL. A 10 mg vial with 2 mL is 5 mg/mL.
- Volume = amount ÷ concentration. 0.5 mg at 5 mg/mL is 0.1 mL.
- Units = mL × 100 on a U-100 syringe. 0.1 mL is 10 units.
The most common mistakes are unit slips: mcg typed as mg (a thousand-fold error), or a U-40 syringe read as U-100 (2.5-fold). The calculator flags amounts larger than the vial and readings that fall between printed marks. More on syringes in U-100 vs U-40 units.
Read how this site works and why it carries no product links.
Common questions
How do you calculate peptide reconstitution?
Three steps. Concentration = vial mg ÷ water mL. Volume = the amount you want to measure ÷ concentration. Units = volume in mL × 100 on a U-100 syringe (× 40 on a U-40). The calculator shows each step with your numbers.
How many units are in 1 mL?
100 units on a U-100 insulin syringe, so 1 unit is 0.01 mL. On a U-40 syringe, 40 units make 1 mL and 1 unit is 0.025 mL. Mixing them up gives a 2.5× error, so the calculator asks which you have.
Does the amount of water change how much peptide is in the vial?
No. The mass in the vial is fixed by the label. Water only changes the concentration: more water means each unit holds less, so the same mass takes more units.
Does this calculator recommend doses?
No. It converts numbers you supply. It has no dose presets, and this site does not publish amounts, schedules or protocols for any substance.
Monthly peptide research digest
One email a month: FDA and WADA status changes, new published research with citations, and updates to the calculators. No product promotions, no vendor deals.