qPCR Efficiency Calculator

Work out qpcr efficiency instantly with clear inputs, formula shown and shareable results.

About qPCR Efficiency Calculator

Converts a standard curve slope into amplification efficiency, where a slope of minus 3.32 corresponds to perfect doubling.

Formula

qPCR efficiency

Amplification = 10^(-1/slope); efficiency (%) = (amplification - 1) x 100; a slope of -3.322 gives 100%

Worked example

With the default values below, qPCR Efficiency Calculator returns Amplification efficiency of 100.081%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Standard curve slopeaccepts -6–-2: -3.32
Coefficient of determinationaccepts 0.8–1: 0.995

Results

Amplification efficiency: 100.081%
Fold amplification per cycle: 2.0008
Slope of a perfect assay: -3.322
Assay assessment: Within the accepted range for quantitative PCR

Step by step

1Values used
2qPCR efficiency
3Amplification efficiency= 100.081
4Fold amplification per cycle= 2.0008
5Slope of a perfect assay= -3.322
6Assay assessment= Within the accepted range for quantitative PCR

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is -3.32 perfect?

It is minus log10(2) inverted: a tenfold dilution shifts Ct by 3.32 cycles when each cycle doubles the product.

What does a shallower slope mean?

Efficiency above 100%, usually caused by inhibitors, pipetting error or primer dimers rather than genuine over-amplification.