Gamepad Deadzone & Trigger Curve
Measure stick range, deadzone and trigger travel — and see what the browser cannot know.
How this test works
The Gamepad API is polled every animation frame while you roll each stick slowly out to its edge and squeeze each trigger through its travel. Three things come out of that. The largest magnitude seen says whether the stick reaches its full mechanical range — a healthy stick hits 1.0 somewhere, and a shortfall shows up in games as being unable to reach full sprint or full turn. The smallest non-zero value says where the reported position stops being exactly zero, which is the edge of the deadzone. And the count of distinct trigger values says whether the trigger is being reported as an analog axis at all. Rolling slowly matters: the deadzone edge is only visible in the moment the value leaves zero, and a fast flick jumps straight past it.
What the results mean
- Stick range
- Furthest deflection reported. Below about 95% means the sensor is not seeing the full mechanical travel.
- Deadzone edge
- Where the reported value stops being exactly zero. A property of controller firmware plus driver, not of the stick alone.
- Trigger levels
- How many distinct values the trigger reported. Three or fewer means it is presenting as a button rather than an axis.
- Trigger onset
- The dead travel before a trigger registers. A small amount is deliberate, so resting finger weight does not fire it.
Common problems and fixes
- The deadzone reads larger than my controller's specification
- You are measuring the chain rather than the controller. The operating system driver adds its own, and on Windows the Xbox driver's is generous by default.
- My triggers show as digital
- That is the browser's standard gamepad mapping presenting them as buttons. It is common and it does not mean the triggers are not analog in games.
- The stick will not reach 100%
- Check for grit around the gate first, then recalibrate at the OS level. On potentiometer sticks a shortfall is ordinary wear; on hall-effect sticks it points at the gate rather than the sensor.
Frequently asked questions
Can a website measure my controller's real deadzone?
No, and any that claims to is reporting the chain. The deadzone is applied in the controller's firmware and the OS driver before the Gamepad API is handed anything, so what a browser observes already has it baked in.
What is the difference between this and a drift test?
Drift asks where the stick rests when untouched. This asks how far it goes and where it starts being heard. A stick can rest perfectly at centre and still fail to reach its edge, and the two faults have different causes.
Why does slow movement matter?
Because the deadzone edge is a single moment — the point where the reported value first stops being zero. Flicking the stick jumps from zero to a large value in one frame and never samples that boundary.