PCR Reaction Concentration Calculator

1. Enter stock concentration
Use the concentration of the reagent solution before it is added to the reaction.

2. Enter stock volume
Enter the volume of that stock pipetted into one reaction.

3. Enter final reaction volume
Use the complete reaction volume after all components are combined.

4. Keep concentration units consistent
If the stock is entered in µM, the displayed final concentration is also µM; if it is ng/µL, the result follows that unit.

5. Review dilution context
The breakdown shows how much of the final reaction volume came from the stock solution.

C1 × V1 = C2 × V2 Final concentration (C2) = Stock concentration (C1) × Stock volume (V1) ÷ Final reaction volume (V2)

Where:

• C1 — starting stock concentration
• V1 — volume of stock added to the reaction
• C2 — resulting final concentration
• V2 — total final reaction volume

Assumptions: The calculation assumes the solute amount is conserved and volumes are additive. It does not account for chemical reactions, binding, degradation, or nonideal volume behavior.

What the result means

Adding 1 µL of a 10 µM stock to a 25 µL final reaction produces a nominal 0.4 µM concentration.

The concentration unit in the result is the same unit used for the stock concentration.

Given:

• Stock concentration = 10 µM
• Stock volume = 1 µL
• Final reaction volume = 25 µL

Calculation:
C2 = 10 × 1 ÷ 25 = 0.4 µM

Result:
0.4 µM final concentration

Interpretation:
Adding 1 µL of a 10 µM stock to a 25 µL final reaction produces a nominal 0.4 µM concentration.