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Attributable Fraction Calculator

Estimate the attributable fraction among exposed individuals from a relative risk.

Reviewed/updated September 8, 2026
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What is the Attributable Fraction Calculator?

Estimate the attributable fraction among exposed individuals from a relative risk. ITS Research Solution keeps the interactive tool above the explanation so you can calculate first and then review the method used.

Formula or method

AFₑ = (RR−1) / RR × 100%.

How to use this tool

Enter the requested values using consistent units, run the calculation and review the main result plus any supporting values. An RR of 2 corresponds to an attributable fraction among exposed of 50%.

Interpretation and limitations

Causal interpretation requires that the relative risk reasonably represents a causal effect and relevant assumptions are met. Always check source data, units, rounding and discipline-specific requirements before using a result in assessed, published, regulated or high-stakes work.

Questions

Frequently asked questions

How is this result calculated?

AFu2091 = (RRu22121) / RR u00d7 100%.

Can I use this result in formal academic or research work?

Use it as a transparent calculation aid, then verify the assumptions, units, rounding and any institution-, journal- or field-specific requirements before formal use.