PCR Mastermix Calculator — Free Lab Calculators

What this is for: Scales every PCR component from one reaction to your reaction count plus overage — the water balances itself.

The formula: total per component = per-reaction volume × (reactions + overage)

How to use:

Enter the reaction volume (µL), number of reactions and overage (%).
For buffer, dNTP mix and each primer, enter the stock and final concentrations; enter Taq polymerase and template DNA as µL per reaction.
Set each component's 'in mastermix?' to Y or N — template is N by default because it is added per tube, not in the mastermix.
Read the per-reaction and mastermix total for each component in the table; water balances each reaction to the full reaction volume automatically.

PCR Mastermix

Per-reaction volume = final conc × reaction volume / stock conc. Template is added per-tube (not in the mastermix). Water balances each reaction to the full reaction volume.

Reaction volume (µL)

Number of reactions

Overage (%)

10X PCR buffer — stock conc. (X)

10X PCR buffer — final conc. (X)

dNTP mix — stock conc. (mM)

dNTP mix — final conc. (mM)

Forward primer — stock conc. (µM)

Forward primer — final conc. (µM)

Reverse primer — stock conc. (µM)

Reverse primer — final conc. (µM)

Taq polymerase — per reaction (µL)

Template DNA — per reaction (µL)

10X PCR buffer — in mastermix? (Y/N)

dNTP mix — in mastermix? (Y/N)

Forward primer — in mastermix? (Y/N)

Reverse primer — in mastermix? (Y/N)

Taq polymerase — in mastermix? (Y/N)

Template DNA — in mastermix? (Y/N)

Effective reactions (with overage)

Buffer per reaction (µL)

Buffer mastermix total (µL)

Water per reaction (µL)

Water mastermix total (µL)

TOTAL mastermix (µL)

Prefer to work offline or keep a copy? The download link is right below.
Download the PCR Mastermix Calculator workbook (.xlsx)

Notes & limits (from the workbook): Per-reaction volume = final conc × reaction volume / stock conc. Scale any component by editing its stock/final concentration. Template is added per-tube (not in the mastermix). Water balances each reaction to the full reaction volume.