Device tools
73 tools that run in your browser. Nothing to install, nothing uploaded.
Browser-based device tests for the things you can actually check from a web page — your camera, your screen, your input devices. These are honest about their limits: a browser cannot read your hardware’s internal health, temperature or firmware, so where a native tool would be more authoritative, these say so. What they are good at is the interactive checks a chatbot cannot do for you — a webcam only tests by showing you a live image, a mouse switch only reveals a fault by how it clicks.
- Accelerometer / Shake TestCheck the accelerometer responds, and see the peak force in g as you move.
- Aspect Ratio CalculatorWork out the aspect ratio of any resolution — and what it is commonly called.
- Audio Dropout MonitorCatch the moments your audio thread starves — the cause of most crackles and gaps.
- Echo / Loopback TestFind out whether the person you are calling can hear themselves through you.
- A/V Sync (Lip-Sync) TestMeasure how far your sound is ahead of or behind the picture, in milliseconds.
- Backlight Bleed TestCheck for backlight bleed on a full-black field — and tell it apart from IPS glow.
- Battery StatusSee your charge level — and why no browser can tell you your battery's health.
- Black Screen TestFill the screen with pure black to find stuck pixels, backlight bleed and cloudy patches.
- BLE Device ScannerCheck a Bluetooth device connects and publishes what it should — from the browser.
- Blue Screen TestLight only the blue subpixel — the dimmest channel, best judged in a dark room.
- Bluetooth Audio Latency TestFind out how many milliseconds your wireless headphones actually add.
- Brightness & Contrast PatternFind out whether your monitor is crushing shadow detail or blowing out highlights.
- OLED Burn-in CheckCheck an OLED for burn-in — and tell permanent wear apart from temporary image retention.
- Channel Isolation TestFind out whether one side is dead, the sides are crossed, or everything is coming out of both.
- Chroma-Key / Green-Screen PreviewSee your key live, and measure the two things you cannot judge by eye.
- Colour Banding / Gradient TestSee whether your display renders a gradient smoothly or breaks it into visible bands.
- Compass / Magnetometer TestCheck the magnetometer, and find out whether your heading has a real reference at all.
- Gamepad / Controller TesterTest every button, trigger and stick — and measure drift as a number.
- Click Speed (CPS) TestMeasure your clicks per second — with switch chatter excluded rather than counted.
- JS CPU BenchmarkA browser speed score, with an honest account of what it does and does not measure.
- CPU Stress / Throttle TestWatch whether your machine slows down under a minute of sustained load — and stays down.
- Dead / Stuck Pixel TestFind dead and stuck pixels with fullscreen colours — and tell the two apart.
- Double-Click Malfunction TestFind out if your mouse is registering two clicks from a single press.
- Frame-Drop DetectorCount the frames your camera actually delivers against the rate it promised.
- Frequency Sweep / Hearing RangeStep through the audible range and find where you stop hearing — and what that does not mean.
- F-Key & Modifier TesterTest F1 to F12 and the modifiers — and see which keys a browser can never receive.
- Gamepad Deadzone & Trigger CurveMeasure stick range, deadzone and trigger travel — and see what the browser cannot know.
- Gamma Calibration ChartEstimate your display's gamma by matching a grey patch against a 50% dither pattern.
- GATT Service BrowserWalk a Bluetooth device's service tree — read-only, and without touching a single value.
- GPS Accuracy TestMeasure how precise your location fix is — without ever reading where you are.
- WebGL GPU BenchmarkA graphics score that admits when the display, not the GPU, was the limit.
- Green Screen TestLight only the green subpixel — the channel your eye reads most sharply.
- Gyroscope TestCheck tilt and heading separately — they are different sensors and fail differently.
- HDR Support CheckFind out whether your display is running HDR — and what that certification actually guarantees.
- Headphone Polarity CheckFind out whether one of your channels is wired backwards, by ear.
- Heart-Rate Monitor TesterCheck your strap pairs, transmits and reports good contact. Not a medical measurement.
- Key Rollover / Ghosting TestFind how many keys your keyboard reports at once — and why six is not a fault.
- Keyboard TesterCheck every key on your keyboard, including the ones the OS normally swallows.
- Local Dimming / Black Level TestSee whether your display dims its backlight in zones, and how coarse those zones are.
- Left-Right Swap DetectorSix randomised tones settle whether your channels are reversed.
- Mic Noise-Floor MeterMeasure the hiss under your voice, in dBFS, with the browser's processing switched off.
- Mic Record & PlaybackRecord a few seconds and hear yourself back, with the level graded rather than guessed at.
- Microphone TestCheck your microphone level and hear exactly what a call sounds like at the other end.
- Ghosting / Motion Blur TestMove an object at a known speed to see how much your monitor smears behind it.
- Mouse Polling Rate TestFind your mouse's real polling rate — not your monitor's refresh rate wearing its name.
- Mouse Button & Scroll TesterCheck every mouse button, both scroll directions and pointer movement.
- Multi-Monitor DetectorSee every display attached to this machine, with the resolution and scaling of each.
- Numpad TesterTest every key on the number pad, including the NumLock behaviour behind most faults.
- Mobile Checkup SuiteWhat a browser can genuinely tell you about a phone — and what it cannot.
- PPI CalculatorPixel density from resolution and screen size, with the distance the pixels disappear.
- QR Code ScannerRead a QR code and see where it goes before anything follows it.
- Reaction Time TestMeasure your visual reaction time, with the display and input latency accounted for separately.
- Red Screen TestLight only the red subpixel to isolate a fault white cannot show you.
- Refresh Rate (Hz) DetectorMeasure the frame rate your browser is actually presenting, and what is capping it.
- Screen Dimensions from DiagonalTurn a screen diagonal into the width and height that decide whether it fits.
- Screen + Mic RecorderRecord your screen with your voice over it — two streams mixed into one file, in the browser.
- Online Screen RecorderRecord your screen in the browser — the file never leaves the tab.
- Screen Size ComparisonCompare two screens by area, width and height — not by the diagonal they are sold on.
- Spacebar CounterCount spacebar presses over a timed window, with auto-repeat filtered out.
- Speaker / Stereo L-R TestCheck each speaker, confirm the channels are the right way round, and find a rattle.
- Stereo Balance TestCheck the stereo image sits dead centre, and find how much correction it needs if not.
- Stuck Pixel FixerCycle colours rapidly over a stuck pixel to try to free it. Works on stuck pixels only.
- Surround Sound 5.1 / 7.1 Channel TestPlay each surround channel in turn — after checking your output can actually carry them.
- Multi-Touch TesterSee how many fingers your screen tracks at once — observed, not merely declared.
- Viewing Distance CalculatorHow far to sit from a screen — by viewing angle, checked against its resolution.
- Typing Speed (WPM) TestMeasure your typing speed in net words per minute, with errors priced in.
- Vibration TestTest the vibration motor — and see why the API returning true proves nothing.
- Voice RecorderRecord a voice memo in the browser and download it. Nothing is uploaded.
- Webcam Exposure / White BalanceMeasure whether your camera is exposing you properly — or exposing the window behind you.
- Webcam Photo CaptureTake a photo with your webcam. No upload, and no EXIF in the file.
- Webcam TestCheck your camera works, and see the resolution and frame rate it actually delivers.
- WebRTC Connection TesterFind out why browser video calls will not connect — before blaming the app.
- White Screen TestFill the screen with pure white to find dead pixels, surface dirt and uneven backlighting.
What a browser can genuinely test, and what it cannot
A web page gets whatever your operating system hands the browser, and nothing else. That is a real set of things: the live image from your camera, the audio from your microphone, every key and button event, pointer movement, gamepad axes, screen resolution, refresh timing and the frame rate a page is actually presented at. It is also a hard boundary. There is no route from JavaScript to CPU temperature, fan speed, SMART attributes, RAM integrity, battery wear level or the internal health of a display panel, so a browser tool that reports those is inferring or inventing them. Every test here states its own limits with its result rather than in the small print.
Why interactive tests are the ones worth running here
The tests that survive in a browser are the ones that need a human in the loop. Nobody can tell you from a description whether your webcam is focused, whether your microphone is picking up a hum, whether a mouse switch is double-firing, or whether a patch of your screen is a dead pixel or a speck of dust — you have to look, listen and click. That is also why these are the checks a chatbot cannot do for you and a spec sheet cannot answer. The measurement side handles what eyes and ears are bad at: drift as a number in millimetres of stick travel, dropouts as a count, latency in milliseconds, jitter between consecutive frames.
Testing a device you are about to buy or sell
A used laptop, phone, controller or monitor can be checked in about ten minutes from a browser, which is usually all the time you get. Work through the parts that are expensive to repair and easy to hide: run the dead pixel test on a fullscreen white and a fullscreen black, exercise every key including the modifiers, click each mouse or controller button several times looking for a double-fire, push both sticks to the rim and watch for a centre that does not return, and open the camera and microphone tests to confirm they enumerate at all. A device that fails any of these in the shop is a device whose price you now have a reason to argue about.
Reading a result that says “inconclusive”
Several of these tests can return a strong negative and only a weak positive, and they say so rather than rounding up. A double-click test that catches a stray second click has proved a failing switch; twenty clean clicks have not proved the switch is healthy, only that it did not misfire during the sample. A refresh rate test measures what your browser was allowed to present, which a power-saving mode or a background tab can cap well below the panel’s capability. Treat a pass as “no fault visible under these conditions”, and repeat anything marginal — on battery and on mains, in a foreground window, and after a reboot.
Frequently asked questions
Can a browser check my CPU temperature, RAM or drive health?
No, and any site that offers to is guessing. The browser is sandboxed away from hardware sensors, SMART attributes and memory addresses by design — there is no web API that exposes them. For those you need a native tool: your operating system’s own health reporting, or something like smartctl for drives. Several tools in the Interpreter category exist to read that output once you have it.
Why does a test ask for camera or microphone permission?
Because there is no way to test a device without opening it. The browser will not hand any page a camera or microphone stream without your explicit consent, and the permission is scoped to this site and revocable from the padlock icon at any time. The stream is rendered locally and never recorded or transmitted — you can watch the network panel stay quiet while the test runs, and closing the tab ends the access.
My hardware passed here but still misbehaves in a game or a call. Why?
A browser test measures the device as the browser is allowed to see it, which is often a best case. Games use exclusive full-screen modes and different input paths, conferencing apps apply their own processing, and both compete for resources a quiet test page does not. A pass means the hardware enumerated and responded correctly here; it does not clear the driver, the application, or the system under real load.
How reliable are these for checking a second-hand device?
Very good for the faults that are visible or interactive — dead pixels, dead keys, double-clicking switches, stick drift, a camera or microphone that does not enumerate — and no use at all for internal wear such as battery chemistry or drive hours. Use them as the ten-minute screening pass that catches the obvious problems in front of the seller, and treat anything about internal condition as still unverified.