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This page describes products and general use; it is not medical advice.
A hand dynamometer is a hand-held device that measures how hard a person can squeeze (grip force) or pinch. This guide is for clinic staff, rehabilitation and occupational-health teams, buyers and students who need to tell the device types apart, understand how the FDA regulates them, and know what a manufacturer’s instructions for use must settle before readings can be compared. It covers hand-held medical devices only, not vehicle or engine dynamometers.
What is a hand dynamometer?
A hand dynamometer is an evaluation tool that measures isometric grip force, meaning hand grip strength (Performance Health, FAQ on hand dynamometers, checked 2026-10-30). The names grip strength dynamometer, hand grip dynamometer and grip dynamometer all describe this same class of device.
The FDA defines the nonpowered version as “a mechanical device intended for medical purposes to measure the pinch and grip muscle strength of a patient’s hand” (21 CFR 888.1250, checked 2026-10-30).
Who uses it: clinicians and therapists who record hand strength, and teams that follow a protocol requiring a repeatable grip measurement. The site’s pre-employment physical exam supply checklist lists a grip dynamometer among exam supplies.
How a hand dynamometer is built and measures force
Hand dynamometers sense force in one of two ways. Some use hydraulics to measure the force, while others use electronic load cells (Performance Health, checked 2026-10-30). A hydraulic unit has a peak-hold needle that keeps the highest reading on the dial until it is reset; a digital unit displays the result automatically. The grip handle has an adjustable position so the device can fit the user’s hand: the fingers wrap one side of the handle and the thumb the other.
Hand dynamometer types: hydraulic, digital and FDA-defined classes
| Type | How it is described | Source |
|---|---|---|
| Hydraulic hand dynamometer | Uses hydraulics to measure force; a peak-hold needle keeps the highest reading until reset | Performance Health FAQ |
| Digital hand dynamometer | Uses an electronic load cell and displays results automatically. The vendor states digital units offer “increased accuracy and no leaking hydraulic oil”; treat that as a vendor claim | Performance Health FAQ |
| Nonpowered dynamometer (FDA) | Mechanical device to measure pinch and grip strength of a patient’s hand. Class I, exempt from premarket notification | 21 CFR 888.1250 |
| AC-powered dynamometer (FDA) | AC-powered device that assesses neuromuscular function or degree of neuromuscular blockage by measuring grip strength with a force transducer. Class II (special controls) | 21 CFR 888.1240 |
The two FDA entries are regulatory definitions, not a shopping taxonomy. The regulation texts say nothing about where a battery-powered digital unit falls, so check the manufacturer’s own regulatory statement for a specific model.
FDA classification of hand dynamometers
Under 21 CFR 888.1250 a nonpowered dynamometer is Class I and exempt from the premarket notification procedures in subpart E of part 807. Under 21 CFR 888.1240 an AC-powered dynamometer is Class II with special controls; it is exempt from premarket notification subject to the limitations in 21 CFR 886.9 (both checked 2026-10-30; 888.1240 was last amended at 84 FR 71818, December 30, 2019). For background on how the agency’s device rules came about, see the Medical Device Amendments of 1976.
Handle positions and specifications that matter
The Jamar dynamometer has five handle positions, which set the grip span (Gasior et al., Open Medicine 2018, checked 2026-10-30):
| Handle position | Grip span |
|---|---|
| I | 3.5 cm |
| II | 4.8 cm |
| III | 6.1 cm |
| IV | 7.3 cm |
| V | 8.6 cm |
In that study, which recruited 135 healthy children aged 5 to 9 and measured them with a digital Jamar, position 2 gave statistically higher results than positions 1 or 3. That finding is specific to children and should not be generalised to adults. The same paper contrasts the Jamar’s fixed positions with an analogue TKK dynamometer that has an adjustable grip span, so the way the span is set differs between designs.
How to choose: criteria that sources state
- Regulatory class. Know whether the product is a nonpowered device (21 CFR 888.1250, Class I) or a force-transducer device that falls under the AC-powered definition (21 CFR 888.1240, Class II).
- The instructions for use. Performance Health advises following the instructional manual that comes with the device.
- Handle adjustment. Confirm the handle can be set to fit the user, and how the grip span is adjusted on that design.
- The same device for repeat readings. Compare serial readings only when they come from the same device and protocol, because different designs report different values: in 110 outpatients aged over 60, the Jamar PLUS+ Digital and a spring-type Takei digital unit read higher on average than the Jamar hydraulic unit. The authors concluded that grip strength is better measured with the same dynamometer in serial measurements (Savas et al., J Clin Med 2023).
Browse diagnostic, monitoring and imaging supplies for related equipment categories.
Safe use and handling basics
Follow the instructional manual that comes with the device (Performance Health). For a hydraulic unit, the manufacturer’s instructions explain how the peak-hold needle is reset, and for any design they explain how the handle is adjusted to fit the user. Studies that compare readings describe their own measurement protocols, so protocol details belong to the instructions for use or the facility’s own procedure, not to this page.
Common mistakes
- Not resetting a hydraulic unit as its instructions describe, so the previous peak stays on the dial.
- Leaving the handle position at a different setting from one session to the next.
- Comparing readings from different device types or models as if they were interchangeable.
- Treating the position 2 finding from children as a rule for adults.
- Searching for “dynamometer” alone and landing on vehicle or engine test equipment, which is a different product class.
Frequently asked questions
Is a grip strength dynamometer the same as a hand grip dynamometer?
Yes in practice. Grip strength dynamometer, hand grip dynamometer, grip dynamometer and hand dynamometer are different names for a device that measures isometric hand grip force.
Is a hand dynamometer an FDA-regulated device?
Yes. A nonpowered dynamometer for pinch and grip strength is Class I and exempt from premarket notification (21 CFR 888.1250); an AC-powered one that measures grip strength with a force transducer is Class II with special controls (21 CFR 888.1240).
What is the difference between a hydraulic and a digital hand dynamometer?
A hydraulic unit measures force with hydraulics and holds the peak on a needle until reset; a digital unit uses an electronic load cell and displays the result automatically.
How many handle positions does a Jamar-style dynamometer have?
Five, with grip spans from 3.5 cm to 8.6 cm.
Sources
Checked 2026-10-30.
- 21 CFR 888.1250, Nonpowered dynamometer, law.cornell.edu/cfr/text/21/888.1250, checked 2026-10-30.
- 21 CFR 888.1240, AC-powered dynamometer, law.cornell.edu/cfr/text/21/888.1240, checked 2026-10-30.
- Performance Health, FAQ about using hand dynamometers for grip strength testing, performancehealth.com, checked 2026-10-30 (manufacturer content).
- Gasior et al., Assessment of Maximal Isometric Hand Grip Strength in School-aged Children, Open Medicine 2018, doi:10.1515/med-2018-0004, PMC5850995, checked 2026-10-30.
- Savas et al., Comparison of Grip Strength Measurements by Widely Used Three Dynamometers in Outpatients Aged 60 Years and Over, J Clin Med 2023, doi:10.3390/jcm12134260, PMC10342845, checked 2026-10-30.
