Peptide Dilution Calculator

Reference

How the Dilution Calculator Works

Diluting a solution means adding solvent to reduce its concentration while the total amount of dissolved solute stays the same. Because that total amount is fixed, the product of concentration and volume before dilution equals the product after dilution -- which is exactly what the standard dilution equation expresses.

The Dilution Equation: C₁V₁ = C₂V₂

C₁ and V₁ describe your stock solution’s concentration and the volume of it you’ll use; C₂ and V₂ describe the working solution you want to end up with. Solved for the unknown stock volume:

V₁ = (C₂ × V₂) ÷ C₁

Whatever volume remains after subtracting V₁ from your target final volume V₂ is the amount of solvent to add. For example, diluting a 5 mg/mL stock down to 1 mg/mL in a final volume of 10 mL requires 2 mL of stock solution made up to 10 mL with 8 mL of additional solvent -- the calculator above performs this arithmetic instantly for whatever values you enter.

Worked Example

Serial Dilutions

A serial dilution repeats the same dilution equation multiple times in sequence, using each step’s result as the next step’s stock concentration -- commonly by a constant dilution factor (e.g. 1:10 at every step) to produce a range of concentrations spanning several orders of magnitude for a standard curve or titration. You can plan a serial dilution with this calculator by working out one step at a time: run the calculator for step one, then use its resulting concentration (C₂ from that step) as the stock concentration (C₁) for step two, and so on. A dedicated serial-dilution calculator that chains these steps automatically is planned for the Full Spec research tools collection.

Why Dilution Accuracy Matters

A miscalculated dilution shifts every downstream concentration by the same proportional error, which can be difficult to detect after the fact if the underlying stock concentration and dilution steps weren’t recorded alongside the result. Documenting C₁, V₁, C₂, and V₂ together -- rather than just the final concentration -- lets anyone reviewing the work verify the calculation and reproduce the preparation exactly. This is the same documentation discipline behind how Full Spec organizes lot-specific analytical testing: a result is only as useful as the record of exactly how it was produced.

For the reverse calculation -- working out a solution’s concentration from a known mass and volume -- see the Peptide Concentration Calculator.