Short answer
To calculate peptide concentration, divide peptide mass by diluent volume. For example, 5 mg reconstituted with 2 mL equals 2.5 mg/mL, which is also 2.5 mcg/uL.
Step-by-step
- Confirm the peptide mass in milligrams.
- Confirm the final diluent volume in milliliters.
- Divide mass in mg by volume in mL to get mg/mL.
- Use the same numeric value as mcg/uL when calculating amount in microliters.
What is the peptide concentration formula?
The formula is concentration = mass / volume. In common peptide calculator units, mg divided by mL gives mg/mL. Because 1 mg is 1000 mcg and 1 mL is 1000 uL, the same number also works as mcg/uL.
How to use concentration after reconstitution
Once concentration is known, multiply mcg/uL by a selected microliter volume to calculate total micrograms. This is arithmetic only; it does not decide what amount should be used in any biological or medical context.
Common concentration mistakes
The most common mistakes are mixing up amount and concentration, converting mg/mL to mcg/uL by multiplying by 1000, or forgetting that the final volume is the diluent volume used in the calculation.
| Peptide mass | Diluent volume | Concentration | Amount in 40 uL |
|---|---|---|---|
| 2 mg | 1 mL | 2 mg/mL = 2 mcg/uL | 80 mcg |
| 5 mg | 2 mL | 2.5 mg/mL = 2.5 mcg/uL | 100 mcg |
| 10 mg | 2 mL | 5 mg/mL = 5 mcg/uL | 200 mcg |
| 10 mg | 5 mL | 2 mg/mL = 2 mcg/uL | 80 mcg |