Peptide calculator
1. Concentration of a vial
The amount in the vial, and the volume of solvent added.
5 mg/mL
5,000 µg/mL
2. Volume for an amount
Uses the concentration above. The volume of solution that holds a given amount of compound.
50 µL
3. Dilution
C1 × V1 = C2 × V2: how much stock to take to make a weaker solution.
Take 0.2 mL of stock and add 0.8 mL of solvent.
4. Molarity
The molar concentration of a solution from its mass, molecular weight and volume.
704.5 µM
0.7045 mM
How the arithmetic works
Concentration is the amount in the vial divided by the volume of solvent: 10 mg in 2 mL is 5 mg/mL, or 5,000 µg/mL. The volume that holds an amount is that amount divided by the concentration, so 250 µg of a 5 mg/mL solution is 50 µL.
A dilution keeps the amount of compound the same: stock concentration times the volume taken (C1 × V1) equals the target concentration times the final volume (C2 × V2). Molarity is the mass divided by the molecular weight, giving moles, divided by the volume in litres.
Solvent is assumed to add no volume of its own, which holds closely for milligram amounts of a lyophilized peptide. Our guides to stability after reconstitution and handling peptides cover the bench side.
For laboratory research use only. This calculator does arithmetic on volumes and concentrations. It is not a dose, and nothing here is medical advice.