Primary data source
Our adult benchmark is based on the iGRIPS international norms published by Tomkinson and colleagues. The systematic review pooled absolute handgrip strength data from 2,405,863 adults aged 20 to 100+ across 69 countries and regions.
Read the open-access source study ↗
What the headline percentile uses
The primary percentile uses only three variables: age, sex and absolute grip strength in kilograms. This mirrors the structure of the published absolute handgrip reference table.
Height and weight do not alter the headline percentile. Height can generate a secondary height-normalized result using the study's kg/m² table. Weight is used only to show grip strength as a fraction of bodyweight.
Interpolation
The paper does not publish every percentile from 1 to 99. When your grip falls between two published anchors, Grip Benchmark estimates your location using linear interpolation between those two strength thresholds.
We do not extrapolate beyond the published range. Values below P5 display “Below 5th.” Values above P95 display “Above 95th.”
Testing protocol
The source norms were statistically harmonized to a reference protocol: hydraulic dynamometer, seated body position, flexed elbow, neutral forearm, handle adjusted to hand size, both hands tested, three repetitions per hand, with the maximum result used.
Consumer dynamometers and different testing positions can produce different readings. For progress tracking, use the same device, handle position and posture each time.
Labels such as “Strong”
Labels are simple Grip Benchmark UI categories, not diagnostic or clinical classifications. The percentile is the more important result. We intentionally avoid calling values “healthy,” “unhealthy,” or making individual health predictions from a single grip test.
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Three core variables. One clear result.