Test Positivity Rate Calculator

Work out test positivity rate instantly with clear inputs, formula shown and shareable results.

About Test Positivity Rate Calculator

Divides positive tests by tests performed, the surveillance indicator used to judge whether testing keeps pace with transmission.

Formula

Test positivity

Positivity (%) = positive tests / total tests x 100; WHO suggested a benchmark of 5% or below

Worked example

With the default values below, Test Positivity Rate Calculator returns Test positivity rate of 8.000%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Positive testsaccepts 0–10,000,000: 240
Tests performedaccepts 1–100,000,000: 3,000

Results

Test positivity rate: 8.000%
Negative tests: 2,760
Tests per positive result: 12.50
Benchmark comparison: Above the WHO 5% benchmark — testing may be insufficient relative to transmission

Step by step

1Values used
2Test positivity
3Test positivity rate= 8.000
4Negative tests= 2,760
5Tests per positive result= 12.50
6Benchmark comparison= Above the WHO 5% benchmark — testing may be insufficient relative to transmission

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 3 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 does positivity matter more than case counts?

It adjusts for testing volume, so a rising positivity rate signals genuinely rising transmission rather than more testing.

Should screening tests be included?

Asymptomatic screening dilutes the rate, so many systems report symptomatic and screening positivity separately.