qPCR Efficiency Calculator
Determine the efficiency of your qPCR assay. Enter the slope obtained from your standard curve to find the percent efficiency and fold amplification per cycle.
Standard Curve Slope
Enter the slope of the linear regression line of Cq/Ct vs. log10(concentration).
Amplification Efficiency
MIQE Guidelines
For valid relative quantification ($DeltaDelta C_q$), assays should have efficiencies between 90% and 110% ($R^2 ge 0.99$).
qPCR Slope to Efficiency Conversion Reference Table
| Standard Curve Slope | Efficiency (E) % | Amplification Factor | MIQE Quality Classification |
|---|---|---|---|
| -3.10 | 110.2% | 2.10 | Acceptable (Upper Bound) |
| -3.32 | 100.1% | 2.00 | Optimal / Ideal (100%) |
| -3.58 | 90.3% | 1.90 | Acceptable (Lower Bound) |
| -3.90 | 80.4% | 1.80 | Poor (Requires Re-design) |
Methodology & Equations
Amplification Factor Formula
Calculates per-cycle fold increase in target cDNA/DNA sequence.
Percent Efficiency Formula
Expresses efficiency as a percentage where 100% represents doubling each cycle.
Frequently Asked Questions
What is qPCR Amplification Efficiency (E)? ▼
qPCR efficiency ($E$) measures the proportion of target template amplified per PCR cycle. Ideal 100% efficiency ($E = 1.0$) means target DNA doubles precisely every cycle ($2.0$-fold amplification).
How is qPCR efficiency calculated from standard curve slope? ▼
Efficiency is calculated using the formula: $E = left(10^{-(1 / text{slope)}} - 1right) times 100%$. An ideal standard curve slope is $-3.322$.
What does an efficiency over 110% or below 90% indicate? ▼
Efficiencies above 110% (slope $>-3.10$) indicate PCR inhibition at high concentrations, non-specific amplification, or pipetting errors. Efficiencies below 90% (slope $<-3.58$) suggest sub-optimal primer design or degraded reagents.
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