PCR Master Mix Calculator

Calculate master mix volumes for multiple PCR reactions. Support for common polymerases including Taq, Phusion, Q5, and OneTaq. Includes controls and overage calculations.

Number of samples to amplify
Extra volume to account for pipetting error

What is a PCR Master Mix?

A master mix is a pre-mixed solution containing all PCR reagents except template DNA and sometimes primers. It ensures consistency across multiple reactions and saves time by reducing pipetting steps.

How to Use This Calculator

Quick guide for PCR setup:

  1. Select your polymerase type
  2. Choose reaction volume (typically 25 μL)
  3. Enter number of samples
  4. Add overage (10-20% recommended)
  5. Include control reactions if needed
  6. View calculated volumes and follow instructions

Common Polymerases

Choose based on your needs:

  • Taq: Standard PCR, fast, economical, no proofreading
  • Phusion: High-fidelity, 50× more accurate than Taq
  • Q5: High-fidelity, robust for difficult templates
  • OneTaq: Versatile, works with crude samples

Why Include Overage?

Overage compensates for:

  • Pipetting errors and dead volume
  • Volume lost in tube walls
  • Extra reactions for backup
  • Standard: 10% for <20 reactions
  • Recommended: 20% for small volumes

Control Reactions

Essential for troubleshooting:

  • Positive Control: Known template that should amplify (validates reagents)
  • Negative Control (NTC): No template DNA (detects contamination)
  • Always include NTC for publication-quality data

Best Practices

Optimize your PCR success:

  • Keep reagents on ice during setup
  • Add polymerase last to master mix
  • Mix thoroughly but avoid excessive vortexing
  • Spin down to eliminate bubbles
  • Prepare master mix in a separate clean area
  • Use filter tips to prevent contamination

Troubleshooting

Q: No amplification in any reactions?
A: Check polymerase activity, verify thermal cycler settings, ensure template quality, check primer design.

Q: Band in negative control?
A: Contamination detected. Clean workspace, use fresh reagents, implement one-way workflow.

FAQ

Q: Can I prepare master mix in advance?
A: Yes, but store at -20°C and use within a few days. Avoid multiple freeze-thaw cycles.

Q: Should primers be in the master mix?
A: Only if all reactions use the same primers. Otherwise, add primers separately to each reaction.