What Does Amplitude Mean on a Massage Gun?
Amplitude is the linear distance, in millimeters, that a massage gun's head travels per stroke, measured with the device running unloaded. It ranges from 7mm on compact devices to 18mm on the longest-stroke models we tracked. It's one of the two headline specs on nearly every listing — alongside RPM — but it doesn't by itself tell you what the device feels like under real pressure.
The one thing to know: Amplitude (the distance the head travels per stroke, in millimeters) and RPM/PPM (how many of those strokes happen per minute) measure two different things, and higher numbers in either do not automatically mean a 'better' device. A short-amplitude gun spun to a very high RPM produces rapid, shallow vibration; a long-amplitude gun run at a moderate RPM produces deeper per-stroke displacement at a slower pace. Neither combination is universally superior — they are a tradeoff, and the honest comparison point is amplitude, RPM, AND stall force together, not any single number in isolation.
Amplitude across popular models
In our Stall Force Reality Index, amplitude ranges from 7mm (Bob and Brad Q2 Mini) to 18mm (TimTam All-New PowerMassager), with the Theragun line (Prime, Elite, Pro, Pro Plus) and Achedaway Pro all clustering at 16mm, and Ekrin's B37S and Opove's M3 Pro at 12mm.
Why amplitude needs stall force alongside it
Amplitude and RPM are the two specs every massage-gun listing leads with, but neither one tells you what happens when you actually press the device into muscle. Stall force — the amount of resistance, in pounds, at which the motor stops moving the arm — is the spec that answers that question, and it is the one manufacturers are least consistent about disclosing. A gun with a long, impressive-sounding amplitude can still stall out under firm real-world pressure if its motor is underpowered, while a shorter-stroke gun with a strong motor can hold its stroke length under load. Read the amplitude and RPM as marketing headlines; read stall force, when it is disclosed and verifiable, as the closer proxy for real-world firmness.
This page reports an equipment-spec definition only, not a health or safety claim.
Frequently Asked Questions
Amplitude is the linear distance, in millimeters, that the device's head travels back and forth in a single stroke, measured with the device running unloaded (nothing pressing against it).
Across the 16 models in our Stall Force Reality Index, amplitude ranges from 7mm (Bob and Brad Q2 Mini, a compact device) to 18mm (TimTam All-New PowerMassager), with most mid-tier and premium devices clustering between 12mm and 16mm.
Unloaded, yes — a longer stroke covers more distance per cycle. Under real hand pressure, though, the device's stall force determines whether that full stroke length is actually maintained; a long-amplitude device with low stall force can lose stroke length once pressed firmly into muscle.
Amplitude is mechanically constrained by the internal arm's travel distance, which a smaller housing physically limits. The Bob and Brad Q2 Mini's 7mm amplitude — the shortest in our dataset — is a direct consequence of its pocket-sized housing, not a spec oversight.