Peptide Dilution Calculator
Solve the C1V1 = C2V2 dilution relationship for the volume you don’t already know.
Calculate a Peptide Dilution
Enter your initial (stock) concentration and target (final) concentration, choose which volume you already know, and enter that volume. The calculator solves for the other volume using C1V1 = C2V2.
Results update instantly as you type. This tool performs a mathematical calculation only — always independently verify results before using them in a laboratory procedure.
How This Calculator Works
Diluting a stock solution lowers its concentration without changing the total amount of peptide present. The relationship between the concentration and volume before and after dilution is fixed, which makes it possible to solve for any one unknown volume once the two concentrations and one volume are known.
Formula and Unit Definitions
C1V1 = C2V2
C1 = initial (stock) concentration · V1 = initial volume
C2 = target (final) concentration · V2 = final volume
If you know V1, the calculator solves V2 = C1V1 ÷ C2. If you know V2, it solves V1 = C2V2 ÷ C1. The volume of diluent to add is always V2 minus V1. Concentrations may be entered in mg/mL or µg/mL; volumes in mL or µL. All values are standardized internally before the calculation runs.
Worked Laboratory Example
Suppose you have a stock solution at 5 mg/mL and need 1 mL of a diluted solution at 1 mg/mL, so V2 is known.
V1 = C2V2 ÷ C1 = (1 mg/mL × 1 mL) ÷ 5 mg/mL = 0.2 mL
Volume of diluent to add = V2 − V1 = 1 mL − 0.2 mL = 0.8 mL
Combining 0.2 mL of the 5 mg/mL stock with 0.8 mL of diluent yields 1 mL of solution at 1 mg/mL.
Accuracy and Limitations
- This calculator only solves standard dilutions, where the target concentration is lower than or equal to the initial concentration.
- It assumes complete, uniform mixing of the stock solution and diluent.
- Results are only as accurate as the concentration and volume values supplied.
See the full calculation methodology for rounding rules and validation logic.
Frequently Asked Questions
What does C1V1 = C2V2 mean?
It is the dilution equation stating that the amount of solute (concentration multiplied by volume) is unchanged when a solution is diluted. C1 and V1 are the initial concentration and volume; C2 and V2 are the target concentration and final volume.
Can I calculate a concentration increase with this tool?
No. This calculator solves standard dilutions, where the target concentration is lower than or equal to the initial concentration. It cannot calculate concentrating a solution.
What is the volume of diluent to add?
It is the difference between the final volume and the initial volume (V2 minus V1) — the amount of solvent or diluent that must be added to the initial volume to reach the target concentration at the final volume.
Can this calculator be used for human or animal dosing?
No. This calculator is not designed for, and must not be used for, human or animal dosing. It is a mathematical tool intended for laboratory research only.