PCR/qPCR Master Mix Calculator
Calculate PCR and qPCR master mix recipes for standard PCR, SYBR Green, probe-based, RT-PCR, and RT-qPCR workflows. Automatically scale reagent volumes, adjust water, apply reaction overage, and generate bench-ready recipes that can be copied directly into laboratory notebooks or electronic lab records.
Reaction Setup
Enter the values that directly control the master mix calculation. Documentation fields and plate mapping are available below when needed.
Documentation Fields
Editable Reagent Recipe
Default reagent recipes reflect common starting conditions for each assay type. Always verify reagent concentrations against validated laboratory protocols or manufacturer recommendations before preparing a master mix.
Primer / Probe Ratio
Automatically calculate primer and probe volumes while maintaining the desired primer-to-probe concentration ratio.
| Component Confirm against validated protocol. | Stock | Final / Target | Per Reaction (µL) | Include in Mix? | Delete |
|---|
Optional Plate / Tube Map
Click one well, or click and drag across wells to assign the selected label/color.
Bench Setup Summary
Master Mix Table
| Addition Order | Component | Per Reaction Volume | Total Master Mix Volume | Include in Mix? | Notes |
|---|
Detailed calculations
ELN-Friendly Method Summary
Formula and Calculation Logic
This calculator scales PCR and qPCR reaction components from per-reaction volumes to an overage-adjusted master mix. Template is included in final reaction volume but is usually added separately after the master mix is dispensed.
C1 is stock concentration, C2 is desired concentration, V1 is stock reagent volume required, and V2 is final reaction volume. Default recipes are starting points and should be checked against validated protocols.
Assumptions
Final reaction volume includes template. Template is typically added separately after the master mix has been aliquoted. Water volume is automatically adjusted to maintain the requested final reaction volume. Default reagent recipes are common starting points, not universal optimized protocols. Laboratory SOPs and manufacturer protocols always take precedence. This calculator performs volume calculations only and does not optimize assay performance.
Example Workflow
A scientist is preparing a 96-well SYBR Green qPCR experiment to measure gene expression across multiple samples. They need a single master mix with 10% overage to compensate for pipetting losses while adding each RNA or cDNA template individually to the reaction plate.
Select qPCR SYBR, enter the final reaction volume, planned reaction count, template volume, and overage.
Review the editable reagent recipe, confirm default concentrations against the validated protocol, and adjust any assay-specific reagent volumes.
Calculate the master mix, review warnings and plate map notes, then copy the bench-ready recipe into the ELN before preparing reactions.
Common Mistakes
Most PCR and qPCR workflows prepare one master mix containing common reagents before dispensing it into wells or tubes. Template is usually added individually to reduce cross-contamination and support multiple samples.
Volumes below about 0.5 µL are difficult to pipette accurately. Prepare an intermediate dilution when very small reagent volumes are required.
Primer, probe, enzyme, magnesium, and template concentrations vary by assay. Confirm defaults using validated protocols or manufacturer recommendations.
Small pipetting losses occur during master mix preparation. A modest overage helps ensure every planned reaction receives enough mix.
Changing one reagent changes the remaining water required to maintain final reaction volume. Recalculate after manual adjustments.
Recording wells, controls, standards, and sample identities before cycling reduces loading errors and simplifies downstream analysis.
Frequently Asked Questions
Why isn't template included in the master mix?
Most PCR and qPCR workflows add template individually after dispensing the master mix. This reduces cross-contamination risk, allows multiple samples to use the same reagent mixture, and simplifies setup. If your protocol specifies otherwise, adjust the reagent table accordingly.
Why does the calculator automatically adjust water volume?
Water balances every reaction to the requested final volume. Whenever another reagent volume changes, the calculator recalculates water so the overall reaction composition remains correct.
Why is extra volume recommended?
Preparing exactly the required volume often leaves insufficient master mix because small amounts remain inside pipette tips and tubes. A modest overage compensates for these losses.
Should I always use the default reagent recipe?
No. Default reagent recipes are common starting points only. Assay-specific optimization, SOPs, kit instructions, and manufacturer recommendations should take precedence.
Why are very small reagent volumes flagged?
Very small pipetting volumes are more affected by technique, pipette limitations, and evaporation. Intermediate dilutions allow larger transfer volumes and usually improve reproducibility.
Does this calculator optimize PCR performance?
No. The calculator performs volume calculations but does not predict amplification efficiency, primer specificity, assay sensitivity, or thermal cycling conditions.