Peptide Mixing Calculator
This calculator works backwards from the syringe. Enter the amount in the vial, the amount you want to measure, and the volume it should fill (for example 20 units). It tells you how much liquid to mix in, and lists other liquid volumes that also land exactly on a marking.
Peptide Mixing Calculator
Mixing calculator
The calculator never suggests an amount.
A whole marking (10, 20, 25 units…) is easiest to read.
Used to round to the nearest marking you can actually read.
Enter the vial amount, your amount and the volume it should fill.
Arithmetic only: it never suggests or assesses an amount. Nothing you type leaves your browser.
The mixing formula
liquid to add = chosen volume × amount in the vial ÷ amount you want to measureThis is the reconstitution formula turned around. Instead of asking what volume an amount takes up, it asks how much liquid makes that amount take up the volume you picked.
Example: a 10 mg vial, 500 mcg to fill 20 units (0.2 mL). 0.2 mL × 10,000 mcg ÷ 500 mcg = 4 mL of liquid, which gives 2.5 mg/mL.
Why pick the volume first
- A whole marking (10, 20 or 25 units) reads exactly. Values between markings don’t.
- Very small volumes magnify reading errors: one unit is 10% of a 10-unit volume, but 5% of a 20-unit one.
- Round liquid volumes (2, 2.5, 3, 4 mL) are easier to measure and to check by hand.
The calculator also shows the U-100 units your amount comes to, and warns when the volume is too small to measure or larger than the syringe.
Liquid to add for a 20-unit volume
| Vial | Amount | Liquid to add | Concentration |
|---|---|---|---|
| 5 mg | 250 mcg | 4 mL | 1.25 mg/mL |
| 5 mg | 500 mcg | 2 mL | 2.5 mg/mL |
| 10 mg | 500 mcg | 4 mL | 2.5 mg/mL |
| 10 mg | 1,000 mcg | 2 mL | 5 mg/mL |
Frequently asked questions
How much bacteriostatic water should I mix with a peptide?
Any volume works mathematically; it only changes the concentration. Pick the volume you want your amount to fill and the calculator gives the liquid to add. See how much bacteriostatic water to add.
Is a mixing calculator different from a reconstitution calculator?
It uses the same formula in the other direction. The reconstitution calculator starts from the liquid you already added; the mixing calculator starts from the volume you want to measure.
What if my vial is labelled in IU?
Choose IU for both the vial and your amount. Mixing IU with mg needs the product’s own IU-per-mg factor, which you enter yourself.
Related calculators and guides
- GuideHow Much Bacteriostatic Water to AddThe volume of bacteriostatic water you add sets the concentration, not the amount.
- CalculatorReconstitution calculatorWork out concentration after adding bacteriostatic water, then the mL and U-100 units for any amount.
- CalculatorSyringe calculatorTurn the units on a U-100 or U-40 syringe into mL and the amount they hold at your concentration, or an amount into units, with the amount per unit.
- GuideHow to Reconstitute Peptides: The MathWhat reconstituting a peptide vial means, the math that turns vial amount and liquid volume into concentration and syringe units, and worked examples.
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Last reviewed · How the calculations work