Enter your Reaction Volume, Number of Reactions, and Overage %, then set concentrations for Buffer, dNTPs, and primers — the PCR Master Mix Calculator works out your Total Master Mix Volume plus individual component volumes for each reagent.
Total Master Mix Volume
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PCR Buffer Volume
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dNTP Volume
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Forward Primer Volume
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Reverse Primer Volume
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Taq Polymerase Volume
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Water Volume
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Overage is extra volume added to compensate for pipetting losses and dead volume in tubes. A 10-20% overage ensures you have enough master mix for all reactions and reduces the risk of running short during preparation.
No, template DNA should be added separately to each reaction tube after distributing the master mix. This prevents contamination between samples and allows for different template concentrations if needed.
Typical final primer concentrations range from 0.1-1.0 µM each. Start with 0.5 µM for both forward and reverse primers, then optimize based on your specific primer pair and PCR conditions.
Many commercial PCR buffers already contain MgCl₂. Check your buffer specification and leave the MgCl₂ fields empty if it's already included. Adding extra MgCl₂ can inhibit PCR reactions.
Fresh master mix works best, but you can prepare it a few hours in advance and keep it on ice. For longer storage, prepare separate aliquots and freeze them. Always add template DNA just before thermal cycling.
Master mixes ensure consistency across reactions, reduce pipetting errors, save time with multiple reactions, and minimize contamination risk. They're essential for reproducible PCR results.
Use calibrated pipettes and aim for ±2% accuracy. For small volumes (<2 µL), consider diluting stocks to pipette larger volumes. Always pipette slowly and check for air bubbles in your tips.
Hot-start polymerases are inactive at room temperature and activate only when heated, preventing non-specific amplification. Regular polymerases are active immediately, which can lead to primer-dimer formation during setup.