Peptide calculator
Calculate concentration, volume and syringe units. Select a profile with source-supported chemistry to add molar conversion.
Reconstitution is one division and one multiplication, and it still goes wrong constantly, because the answer arrives in three different units and a syringe is graduated in a fourth. This tool does the arithmetic in all four at once. It computes what is in the solution; it does not tell you what to do with it.
Choosing a compound loads its source-supported reference mass, which is what turns micrograms into nanomoles. Leave it unset and the calculator still does the concentration arithmetic.
Reconstitution calculator
Enter how much peptide is in the vial and how much diluent (e.g. bacteriostatic water) is added. The tool returns the resulting solution concentration — and, for any amount you type, the volume it corresponds to. This is educational arithmetic, not a dosing recommendation.
Enter an amount to see the volume it corresponds to.
Educational concentration mathematics only. This tool does not recommend a dose, amount, or protocol, and nothing here is medical advice. Many peptides are not authorized by Health Canada for human use — see our reconstitution and bacteriostatic-water guides for context.
What the calculator is actually computing
Concentration is the mass in the vial divided by the volume of diluent added. A 10 mg vial reconstituted with 2 mL of bacteriostatic water gives 5 mg/mL, which is the same thing as 5,000 mcg/mL. Nothing about the peptide changes that number — the arithmetic is identical for BPC-157 and for semaglutide.
The volume corresponding to an amount is that amount divided by the concentration. 250 mcg out of a 5,000 mcg/mL solution is 0.05 mL. Where people go wrong is the last step: a U-100 insulin syringe is marked in units where 100 units = 1 mL, so 0.05 mL reads as 5 units. A U-40 syringe, still sold in some markets and common in veterinary supply, puts 40 units in 1 mL — the same 0.05 mL reads as 2 units on that barrel. Choosing the wrong graduation is a 2.5-fold error, and it is the single most common mistake in this arithmetic.
Why the molar readout matters
Micrograms describe mass. Nanomoles describe how many molecules there are. Two peptides at the same mass concentration are not at the same molar concentration if their masses differ — and in this field they differ enormously: ipamorelin is about 712 Da, tesamorelin about 5,136 Da. The same 250 mcg is roughly seven times more molecules of the first than of the second.
That conversion needs the molecular mass of the selected reference form. Selecting a compound above loads its source-supported reference mass and states whether the basis is an average mass or an isotope-specific mass. Its profile links the supporting registry records and, where applicable, official medicine labels. Where no source-supported reference mass exists, the molar readout stays hidden: an unmodified sequence alone cannot represent an acylated, cyclised or PEGylated molecule.
A note on diluent volume
The volume you enter is the volume of diluent added, and the calculator treats the final volume as the same number. For the small masses involved that is the convention everyone uses and the error is well under a percent — a few milligrams of lyophilised powder displaces almost nothing in a millilitre of water.
Choosing a larger diluent volume does not change how much peptide is in the vial. It changes how precisely you can measure a fraction of it: more diluent means more syringe units per microgram, and a reading that is easier to hit. That is the whole trade-off, and it is why the same vial is reconstituted differently by different people.
Calculators set up per compound
Each preset starts with a vial amount you can edit. Molar conversion appears only when the profile has a source-supported reference mass; unresolved forms are explained on their calculator page.
FAQ
- How do I calculate peptide reconstitution?
- Divide the amount of peptide in the vial by the volume of diluent you add. A 5 mg vial with 2 mL of bacteriostatic water is 2.5 mg/mL, or 2,500 mcg/mL. To find the volume corresponding to a given amount, divide that amount by the concentration.
- How many units on an insulin syringe is 0.1 mL?
- On a U-100 syringe, 10 units — the scale puts 100 units in 1 mL. On a U-40 syringe it is 4 units. Always check which graduation your syringe uses before converting a volume into units; the two differ by a factor of 2.5.
- Does the type of peptide change the reconstitution math?
- No. Concentration is mass divided by volume regardless of the compound. The compound only matters if you want the result in molar terms, which requires its molecular mass.
- Does bacteriostatic water change the concentration?
- The volume of any diluent sets the concentration, whichever one is used. Bacteriostatic water contains a small percentage of benzyl alcohol as a preservative; sterile water does not. That choice affects storage, not the arithmetic.
- How much does the powder add to the final volume?
- Very little. A few milligrams of lyophilised peptide displaces a negligible fraction of a millilitre, which is why the diluent volume and the final volume are treated as the same number in every calculator of this kind.