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Odds Ratio and Relative Risk from 2×2 Table Calculator

Epidemiological association measures from a contingency table.

Calculates odds ratio OR = (a·d)/(b·c) and relative risk RR = (a/(a+b)) / (c/(c+d)) from a 2×2 exposure/outcome contingency table.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

OR = (a·d)/(b·c); RR = (a/(a+b))/(c/(c+d))

In depth

Calculates odds ratio OR = (a·d)/(b·c) and relative risk RR = (a/(a+b)) / (c/(c+d)) from a 2×2 exposure/outcome contingency table.