Qpcr Efficiency Calculator
Reaction & Curve Inputs
Amplification Efficiency
Standard Curve Preview
Slope alone does not specify an intercept.
Linear regression of mean Cq values • example data
Curve & Efficiency Summary
| Item | Value | Basis |
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Formula & Interpretation
Efficiency (%) = (10−1/slope − 1) × 100
Amplification factor = 10−1/slope
At slope −3.32: efficiency ≈ 100.1%; factor ≈ 2.001 per cycle.
Frequently Asked Questions
Why must slope be negative?
Higher starting quantities should reach the fluorescence threshold in fewer cycles. With Cq plotted against log10(quantity), this gives a negative slope. Positive or zero slopes are rejected.
Can I enter replicates?
Yes. Enter up to three Cq measurements per dilution. Mean Cq at each row is used in ordinary least-squares regression with equal weight per dilution. Blank replicate cells are ignored; no values or rows are silently removed.
Does a high R² guarantee assay quality?
No. Check specificity, negative controls, replicate variation, inhibition and the validated working range. R² thresholds and efficiency acceptance criteria depend on the protocol.
What does this calculator calculate?
Amplification efficiency and the per-cycle amplification factor from slope. Dilution-series mode additionally estimates slope, intercept, R² and the log10 range of relative input quantities.
Which values and formula should I use?
Enter a negative slope from Cq versus log10(quantity), or a constant serial dilution factor greater than one and its Cq measurements. Efficiency is (10^(−1/slope) − 1) × 100%. The ideal 100% slope is approximately −3.321928.
Why might results differ from another source?
Tools can fit all individual replicates, mean Cq values, weighted regressions or different ranges. This tool fits row means equally. The 90–110% guide is a screening convention, not a universal MIQE acceptance rule.
Does the result update automatically?
Yes. Edits immediately update the results and measured curve when valid. Changing dilution factor relabels the same Cq data; it does not fabricate new observations. Load Example replaces the table with labeled example data.
Key References
Qpcr Efficiency Calculator Calculate qPCR amplification efficiency from the slope of the standard curve. — free online calculator.