Relative Risk Calculator
Compare event probabilities between exposed and control cohorts.
How the relative risk calculator works
Relative risk compares event probability in an exposed cohort with event probability in a control cohort. Each risk divides events by the full group total, then the exposed risk is divided by control risk. This calculator also reports absolute risk difference because a ratio alone can make a small baseline change look large without showing the actual probability-point change.
The defaults give exposed risk 40 divided by 50, or 0.8, and control risk 20 divided by 50, or 0.4. The verified relative risk is 2, meaning the observed exposed risk is twice the control risk. Their verified risk difference is 0.4, an absolute increase of 40 percentage points in this table.
Reading relative risk calculator results privately
Relative risk requires cohort-like data where group totals and event probabilities are meaningful. A zero control risk makes the raw ratio undefined even when risk difference remains available. This descriptive result has no confidence interval, adjustment for confounders, or causal interpretation. Reversing group labels returns the reciprocal ratio and reverses the difference sign. This relative risk calculator calculation runs entirely in your browser, so the numbers you enter never leave your device.
Frequently Asked Questions
Why report risk difference as well as relative risk?
Risk difference shows the absolute probability-point change, while relative risk shows the multiplicative change from baseline.
What does relative risk below one mean?
The observed event risk is lower in the exposed group than in the control group under the entered orientation.
Is the relative risk calculator private?
Yes. Its inputs and results stay in your browser. Bushe.co does not upload or store the values used in this calculation.
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