Peptide concentration calculator
Work out the concentration of a peptide solution in mg/ml and µg/µl, its molar concentration in mmol/L from the molar mass, and the volumes for a dilution. Presets fill in each pen on our Peptide Pens page with its amount in mg and its volume in ml. For laboratory calculations.
Results
- Concentration
- mg/ml · µg/µl
- Molar concentration
- mmol/L
- Stock volume needed
- ml
- Diluent to add
- ml
How to use the calculator
Enter the amount of peptide in mg and the volume of solution in ml. The concentration appears as you type. To see the molar concentration as well, add the molar mass in g/mol. To plan a dilution, add the target concentration in mg/ml and the final volume in ml: the calculator gives the stock volume to take and the diluent to add to reach that final volume.
Each pen is labelled with its total amount and its volume, so choose a pen from the preset list and its amount and volume are filled in for you. The preset links to the pen's page.
Worked example:
BPC-157 20mg in a 3 ml pen is 6.67 mg/ml. With a molar mass of 1419.5 g/mol that is 4.70 mmol/L.
A dilution example: a stock of 20 mg/ml, diluted to a target of 5 mg/ml in a final volume of 3 ml, needs 0.75 ml of stock and 2.25 ml of diluent.
The formulas
- Concentration (mg/ml) = amount (mg) ÷ volume (ml).
- Molar concentration (mmol/L) = concentration (mg/ml) ÷ molar mass (g/mol) × 1000.
- Stock volume (ml) = target (mg/ml) × final volume (ml) ÷ stock concentration (mg/ml).
- Diluent (ml) = final volume (ml) − stock volume (ml).
The target cannot be stronger than the stock, because a dilution only makes a solution weaker. If a field is empty, not a number or zero, the calculator says so instead of showing a result.
Units: mg, µg and mM
1 mg is 1000 µg. A concentration of 1 mg/ml is the same as 1 µg/µl and 1 g/L, so the two mass concentrations shown are always the same number. A molar concentration in mmol/L is the same as mM. The molar mass is the mass of one mole of the peptide in g/mol, taken from the supplier's data sheet; it is different for every peptide.
Related
- Peptide pens: the amount and volume of every pen, with its concentration.
- Peptide pen vs vial: why a pen states its concentration and a vial does not.
- Delivery and returns.
The calculator is for laboratory calculations and does no more than the arithmetic above. Check every result against your own records.