Sensitivity and specificity calculator
Enter the four confusion-matrix cells: true positive, false negative, true negative and false positive.
2 × 2 matrix
| Test result | Condition present | Condition absent |
|---|---|---|
| Fill in the fields above — the result is computed on this page. | ||
How do I use this page?
- Enter TP, FN, TN and FP.
- Inspect sensitivity and specificity.
- Compare PPV, NPV, F1 and likelihood ratios.
What this page does not do: Results describe the entered sample and classification threshold. Transferring PPV and NPV to a population with different prevalence can be misleading. This tool does not replace clinical judgment.
Further reading
Theory — how do sensitivity and specificity differ?
Sensitivity is the share of cases detected by a test among all people who actually have the condition, while specificity is the share correctly excluded among those who do not. The calculator computes these from four confusion-matrix cells: true positive, false negative, true negative and false positive. Positive and negative predictive values also depend on how common the condition is in the tested population. Sensitivity and PPV are not the same: sensitivity conditions on the true state, while PPV conditions on the test result.
Frequently asked questions
Are sensitivity and PPV the same?
Why does PPV change between populations?
See also
A/B test calculator
Compare two proportions in an A/B test. Calculate conversion rates, difference, uplift, z score, p value and c
A/B test planning — sample size, MDE and duration
Plan a two-proportion experiment, estimate detectable effect and traffic duration.
ACF and PACF autocorrelation calculator
Calculate ACF and PACF across time-series lags. Review the chart, reference bounds and coefficient table.