Frailty Index Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Functional and geriatric scales are designed to summarize patterns that a clinician or caregiver has already observed. Frailty Index Calculator converts those observations into the specific score used by this tool.

What this calculator does

Frailty Index Calculator uses Deficits present and Deficits assessed to produce the frailty index used by this calculator. It only uses the fields shown in this calculator; it does not silently add tests, diagnoses, symptoms, or clinical variables that are absent from the interface. Uses standard health-calculator relationships where a stable equation exists; complex or policy-dependent tools expose assumptions/points so the result can be checked against the current clinical or public-health source.

How to use it

Enter or select Deficits present and Deficits assessed. Score what is actually observed for the person under the scale’s intended conditions rather than the best performance you think is possible. If an input is unknown, it is better to leave the calculation unresolved than to invent a value.

How the calculation works

Frailty index = number of deficits present ÷ number of deficits assessed. The tool also expresses the fraction as a percentage.

Example

Using the calculator’s prefilled demonstration values, the primary output is 0.2, labeled “Frailty index”; Percent deficits is 20%. That sample is useful for checking the calculation path, but real interpretation should use verified measurements from the same clinical or study context.

How to interpret the result

Read frailty index as a summary of the selected functional, cognitive, risk, or comorbidity items. It is most useful for communication and tracking when the same version and scoring conditions are used consistently over time.

Limitations and notes

Performance scales can vary with acute illness, fatigue, assistance, environment, language, hearing/vision, cognition, and who performs the assessment. Local cutoffs and care plans may differ, so repeated standardized assessment is often more informative than one isolated score.