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PCR Master Mix Calculator

Work out the volume of every reagent in a PCR master mix from its stock and final concentration. Use it whenever you set up several PCR reactions at once, so each tube gets the same mix and you don't run short.

Enter how many reactions you're running and check the reagents match your kit. We'll tell you how much of each to add to the master mix, and in what order.

Include your controls.

Rounded up to whole reactions.

%

Total volume in each tube.

µL

Added to each tube separately.

µL
Components

Edit these to match your kit. Water fills up the rest of the reaction.

  • Optional: remove it if your buffer already contains MgCl₂.

  • U/µL
    U
Add:
Enter the number of reactions and press Calculate to see your master mix.

How it's calculated

Volume per reaction = final concentration ÷ stock concentration × reaction volume

Polymerase per reaction = units needed ÷ stock (U/µL)

Water = reaction volume − all other components − template

Reactions to mix = number of reactions × (1 + extra %), rounded up

Total per reagent = volume per reaction × reactions to mix

This is the same C1 × V1 = C2 × V2 relationship used for any dilution, applied to each reagent. The extra reactions cover liquid lost on pipette tips and tube walls.