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qPCR Dilution Reagent Volume Calculator

The qPCR Dilution Reagent Volume Calculator determines how much stock solution and diluent are needed to prepare a target qPCR working solution using C1V1 = C2V2. Enter the stock concentration, desired final concentration, and final preparation volume; the calculator solves for the required stock aliquot and the remaining diluent volume.

It is suitable for planning standard, primer, probe, template, or other dilution steps when a simple single-stage dilution is appropriate. The tool does not define assay-specific target concentrations. Use concentration units consistently and follow your validated qPCR workflow for actual preparation.

Inputs

units
units
µL
Result
—
Stock volume needed
Diluent volume—
Dilution factor—
Stock share of final volume—

1. Enter stock concentration
Use the concentration of the solution you are diluting.

2. Enter the target concentration
Use the concentration required for the working solution or dilution step.

3. Enter final volume
Specify the total volume you want after stock and diluent are combined.

4. Keep concentration units matched
C1 and C2 must use the same concentration unit.

5. Prepare from the result
The main result is the stock aliquot; the breakdown gives the diluent volume needed to reach the selected final volume.

C1 × V1 = C2 × V2 Stock volume (V1) = C2 × V2 ÷ C1 Diluent volume = V2 − V1

Where:

  • C1 — stock concentration
  • V1 — stock volume to pipette
  • C2 — target concentration
  • V2 — final total volume after dilution

Assumptions: This is a one-step ideal dilution. It assumes concentration is conserved and that stock plus diluent volumes are additive.

What the result means

A tenfold dilution of the stock produces the target concentration in a 100 µL final preparation.

C1 and C2 must be expressed in the same concentration unit.

Given:

  • C1 = 100 units
  • C2 = 10 units
  • V2 = 100 µL

Calculation:
V1 = 10 × 100 ÷ 100 = 10 µL
Diluent = 100 − 10 = 90 µL

Result:
10 µL stock + 90 µL diluent

Interpretation:
A tenfold dilution of the stock produces the target concentration in a 100 µL final preparation.

What if the target concentration is higher than the stock?

That cannot be achieved by simple dilution because adding diluent only lowers concentration. Use a more concentrated stock or a concentration method appropriate to the material.

Can C1 and C2 use different units?

Convert them to the same concentration unit first. Mixing units such as nM and µM without conversion will produce an incorrect stock volume.

What if the required stock volume is too small to pipette accurately?

Prepare an intermediate dilution or increase the final preparation volume so the aliquot falls within a reliable pipetting range for your equipment and method.

Is this suitable for serial standards?

It can calculate each individual dilution step. For a serial dilution series, verify the intended factor and transfer volume at every stage rather than assuming one step describes the entire series.

Does the formula account for qPCR chemistry?

No. It only handles the concentration-volume relationship. Assay performance, primer/probe behavior, matrix effects, and standard preparation requirements come from your validated method.