Touchpad Tester

Most touchpad testers draw a line that follows your finger. That is satisfying to watch but it answers the wrong question. A trail can only appear where the pad already responded, so a dead patch produces no line at all, and an absence of line is easy to miss. The part of the surface that failed is exactly the part that leaves nothing behind.

The coverage grid inverts that. The surface starts fully dark and every cell lights the first time the pointer passes through it, so the test is not what you drew but what is still unlit when you have swept everywhere. Move your finger slowly in overlapping passes, corner to corner and edge to edge, until the whole grid is green. Any cell that stubbornly stays dark after your finger crossed it is a spot the touchpad did not register, and that is the hard evidence of a dead zone.

Dead zones tend to appear where a pad gets the most use: a band across the centre where the cursor lives, or the lower corners on a clickpad where people press to click thousands of times a day. If the grid confirms a gap there, no driver setting will bring it back, and the finding is worth having in hand before a warranty conversation.

A touchpad usually carries three separate button actions, and folding them into one counter hides the fault you are looking for. The primary click is the left button or a one-finger tap. The secondary click, the right button, is a two-finger tap or a press in the bottom-right corner on most trackpads. A middle click exists on some pads and many external mice. This tool keeps a count for each, so you can confirm the one that felt dead really is dead, or prove it still works and the problem lies elsewhere.

The double-click gap is the measurement that turns a vague complaint into something you can see. When the tool pairs two quick clicks into a double, it prints the time between them in milliseconds. Two symptoms show up clearly here. If double-clicks keep failing, your two presses are probably landing further apart than the system threshold, and the gap reading confirms how far. If single deliberate clicks are firing as doubles on their own, the microswitch is likely chattering, bouncing one physical press into two electrical contacts, and you will see doubles appear from presses you know were single.

Because a real double-click is two clicks close together in both time and place, the tool only pairs clicks that landed within a short window and near the same spot. Two unrelated clicks seconds apart, or on opposite sides of the pad, stay counted as separate single clicks, which keeps the primary count honest.

Before deciding a touchpad is broken, rule out the settings that mimic a fault. Many laptops disable the pad automatically when a mouse is plugged in, so a completely dead surface can simply be that option doing its job; unplug the mouse and try again. Tap-to-click can be switched off, which makes a healthy pad feel unresponsive to light taps while a firm press still clicks. Scroll direction and two-finger scrolling each have their own toggle, and a reversed or disabled setting looks like a broken gesture.

Sensitivity and palm rejection matter too. Palm rejection deliberately ignores contact it thinks is an accidental brush from your hand while typing, and an aggressive setting can swallow real input near the edges. If the coverage grid shows gaps only around the border, suspect palm rejection before hardware. A genuine hardware dead zone tends to be sharply bounded and repeatable in the same place no matter how you approach it.

For the keys beside the pad, the Keyboard Tester checks rollover and stuck keys, and for a game controller the Gamepad Tester covers buttons, triggers, and stick drift the same way this page covers the pad.

It can only see what the browser passes to the page, and the operating system takes a cut first. System gestures such as three- and four-finger swipes for switching apps or showing the desktop are usually handled before a web page is told anything, so they will not appear in the counters even when they work perfectly. A quiet gesture here is inconclusive rather than proof of a fault.

It cannot measure pressure, tracking speed in real units, or how smooth the pad feels, because the browser reports pointer positions and not force or a calibrated velocity. It cannot separate a touchpad from a mouse when the system has already merged them into generic pointer events. And the coverage grid resolves to whole cells, so a dead spot smaller than one cell can hide; sweep slowly and repeatedly rather than relying on a single fast pass.

What it does do is concrete and local: it lights a grid so unlit cells reveal dead zones, counts each button on its own, measures the double-click gap so chatter and slow response become visible, and sorts a pinch from a scroll. Nothing about how you move or click leaves your browser.