How to use the Tablet Pen Pressure Test
- Draw on the canvas. Use your tablet pen, display pen, Apple Pencil or stylus exactly as you would in a painting app. The readouts panel shows the pointer type, pressure, tilt, twist, barrel pressure, contact size and how many readings per second the browser receives, while the graph traces pressure over the last five seconds.
- Read the verdict under the canvas. After each stroke you get a report — samples, pressure range, the finest pressure step seen, tilt range — and a plain-language diagnosis. If the browser sees a mouse, or a pen whose pressure never changes, it lists the likely causes for your operating system.
- Run the two exercises. Light → heavy asks you to trace a guide from feather-light to full pressure and tells you how much of the range you actually reached. Steady line measures how evenly you hold medium pressure.
- Shape the pressure curve. Drag the two handles, or pick Linear, Soft, Firm or S-curve. New strokes use the curve right away, and the preview strip under it shows a stroke going from no pressure to full and back. Choose whether pressure drives Size, Opacity or both.
- Keep the result. Download PNG saves your test strokes, which is handy when you report a problem to a tablet maker’s support team. Clear wipes the canvas.
What a browser actually receives from your pen
Browsers read pens through Pointer Events, a web standard that reports every input — mouse, finger, pen — as the same kind of event with extra fields. pressure runs from 0 to 1. tiltX and tiltY give the pen’s angle toward each axis, from −90° to 90°. twist is the rotation of the pen around its own axis, 0–359°, which only a few pens such as the Wacom Art Pen report. tangentialPressure is the airbrush finger wheel, from −1 to 1. Newer browsers add altitudeAngle and azimuthAngle, the same tilt expressed the way Apple Pencil thinks about it.
The standard also says what happens when hardware has no pressure sensor: the browser must report 0.5 while a button is pressed and 0 otherwise. That is why a mouse always shows exactly 0.500, and why a pen stuck on 0.5 is the classic sign that pressure is being lost somewhere between driver and browser.
Pens report faster than screens refresh. A drawing tablet typically sends somewhere between a hundred and a few hundred positions per second, while the page usually gets one event per display frame. The browser bundles the in-between readings as “coalesced” events, and this test draws every one of them; the per event figure in the report shows how many arrive in each bundle. Painting apps do the same thing, which is why a quick stroke stays curved instead of turning into a polygon.
Pressure levels: why you may see 1/1024
Tablets are sold on pressure levels — 2,048, 4,096, 8,192. The report estimates the finest step it saw by looking at the smallest gap between distinct readings in a stroke. On Windows that number usually lands near 1/1024, whatever the box says, because the Windows pointer API passes pen pressure to applications on a 0–1024 scale. It is a limit of that path, not a fault in your pen.
That says little about how a pen feels to draw with. Beyond a few hundred usable steps, the difference between levels is far smaller than the wobble in any human hand — try the Steady line exercise and look at the standard deviation. Drawing feel depends much more on the activation force (how lightly the tip starts registering), the shape of the curve, nib friction and latency.
Reading the numbers
| Readout | Healthy pen | Warning sign |
|---|---|---|
| Pointer | pen |
mouse while you hold a pen |
| Pressure | Changes smoothly from near 0 to near 1 | Stuck at 0.500, or jumps only between 0 and 1 |
| Tilt X / Y | Changes as you lean the pen | Always 0° (normal for many pens, not a fault) |
| Rate | Well above your screen’s refresh rate | Under 60 Hz on a fast stroke |
| Per event | 2 or more on a fast stroke | Always 1, with angular-looking curves |
| Buttons | tip, barrel or eraser as you press them |
No change when you press a side button (check the driver’s button mapping) |
Tilt deserves a note. Many entry-level tablets have no tilt sensor at all, and some browsers on some systems do not pass it through even when the hardware has it, so “Tilt X / Y: 0° / 0°” is not a reason to return a tablet.
When pressure is missing
Work through the causes in order of likelihood. On Windows, the usual culprit is the Windows Ink setting in the tablet driver: browsers rely on it, while some painting apps can use the older Wintab interface instead, so pressure can work in Krita and fail in Chrome on the same machine. On a Mac, the driver needs permission under Privacy & Security before it can deliver anything beyond mouse movement. On an iPad, check which pencil you have — several models sense tilt without pressure. Remote desktop sessions, virtual machines and some screen-recording tools turn a pen into a mouse on the way through.
If the test shows healthy pressure but your painting app still draws flat lines, the problem is inside that app: a brush setting with pressure switched off, or an app-specific tablet profile in the driver.
Tips from practice
Set the curve in one place only. Your tablet driver, your operating system and your painting app can each apply a pressure curve, and they stack. Pick one — usually the app, so your settings travel with your brushes — and keep the others linear.
Test light pressure before you buy. Draw the faintest hairline you can in the Light → heavy exercise. If the first reading is already above 0.15, fine sketching will feel heavy-handed whatever curve you choose.
Re-test after every driver or system update. Updates are the most common reason a tablet that worked yesterday suddenly draws like a mouse. A ten-second scribble here tells you whether to blame the driver or the app.
Watch the nib. A worn, flattened nib changes friction and the angle at which pressure registers. If your Steady line results drift over a few weeks, swap the nib before you change your curve.
Match brush size to your screen. A 20 px brush covers very different physical widths on a 92 PPI monitor and on a 264 PPI tablet; the Screen Resolution & PPI Calculator and the Procreate Brush Size Converter help you translate between them.