How to use the pen pressure test
Draw on the canvas with your pen, on a drawing tablet, a pen display, an iPad or an Android tablet. The gauge shows the pressure the browser receives right now, from 0 to 100%, and the stroke gets wider the harder you press. The graph under the gauge keeps the last five seconds, so a single press from light to heavy shows as a rising curve.
The chips under the gauge light up while each part of the pen is in use and stay outlined once it has been seen: Tip while the pen touches, Hover while it's held just above the surface, Barrel for the side button, Eraser for the back end, Tilt and Twist once the browser has reported either. The Readings panel (tap Readings on a phone) lists every value from the pen: tilt X and Y, altitude and azimuth, twist, tangential pressure from an airbrush wheel, contact size, and the report rate.
Use Full screen for a bigger drawing area: every control stays inside it.
The guided tests
- Pressure ramp: draw one slow stroke along the band, starting as light as the pen allows and pressing harder until you reach full pressure. The tester plots the pressure along the stroke and flags jumps between neighbouring readings, a value that stays stuck while you keep pressing harder, noise on the curve, very few distinct steps, and a reading that stops short of full pressure.
- Straight line and Diagonal line: draw slowly along the guide, ideally against a ruler. The tester fits a straight line through the points and splits what's left into fine shake (jitter) and slow drift (wobble). Slow diagonal lines are the classic jitter test for drawing tablets, because that's where a wavy line shows most.
- Tilt: rest the tip on the centre dot and lean the pen right, towards you, left and away. Each quarter of the dial fills once the pen has leaned 25° that way.
How to read the results
Range seen is the lightest and heaviest pressure in any stroke. A pen in good order reaches 100% when pressed firmly and a few percent at its lightest touch. If the top stays well below 100%, the pressure curve in the pen's settings may be set too firm; if a light touch already reads high, it's set too soft.
Distinct values counts how many different pressure readings the browser passed on. It isn't the pen's pressure levels: the driver, the operating system and the browser can all reduce the steps, so a pen sold with thousands of levels can show fewer here. A count in the dozens after a long ramp means pressure arrives in coarse steps, which shows in brushes as banding.
Jitter is in pixels on your screen, as the root mean square of the shake around the line. Up to 0.5 px reads as steady and above 1.2 px as visible jitter: these thresholds are this tool's own rule of thumb, not a standard. Wobble is the largest slow drift from a straight line; with a ruler, the tester calls out more than 3 px, again its own rule of thumb.
The pressure ramp's flags use limits of this tool's own too: a jump of more than 15% between two neighbouring readings, one value held for more than 0.3 s in the middle of the stroke, noise above 2% RMS around the curve, fewer than 48 distinct values when the stroke had more than twice as many samples, and a top below 95%.
Report rate is how many samples per second arrive while the pen moves. The tester counts every sample, including those the browser merges between screen frames. Move the pen steadily for a second or two and read the peak; to compare it with your screen, run the refresh rate test.
When the pen reports no pressure
Under the Pointer Events standard, any input without a pressure sensor reports exactly 0.5 while it touches and 0 otherwise. That's what you see for a mouse, so the tester labels a mouse "no pressure data" and doesn't read a finger as pressure at all, instead of showing a fake reading. If your pen is labelled Mouse, or its pressure stays at 50% however hard you press, the browser is getting it without pressure:
- On Windows, check the Windows Ink option in the tablet's driver. Huion and XP-Pen both say to turn it on for programs that use Windows Ink.
- Update the tablet driver, unplug and reconnect the tablet, and restart the browser.
- Try another browser: the notes under the canvas say what yours can't report.
- On an iPad, every browser runs on Apple's WebKit engine, so switching from Chrome to Safari won't change the values. Check which Apple Pencil you have: Apple lists no pressure sensitivity for Apple Pencil (USB-C).
Testing a mouse instead? The mouse tester checks buttons, double clicks and polling rate. For finger input on the same screen, the touch screen test counts multi-touch points and finds dead zones. A pen display with a stuck pixel shows up in the dead pixel test.
Privacy
Everything runs in your browser. Your drawing never leaves the page, and a shared result link holds only the numbers the tester measured.