About CheckYourDisplay
Free browser-based tests for displays, speakers, microphones, cameras and input devices, with plain explanations of what each result means and what a browser cannot measure.
What CheckYourDisplay is
CheckYourDisplay is a collection of 53 tests in 6 categories that run in any modern browser, on a desktop, laptop, phone, tablet or TV. Fill the screen with a solid color to look for dead pixels, estimate your refresh rate, send a tone to one speaker at a time, watch your microphone level, preview your camera, or press every key and see it light up. There is nothing to install, no account and no advertising.
It exists to make basic hardware checks quick and trustworthy: checking a new or second-hand monitor before the return window closes, making sure both speakers work, or confirming a microphone and camera before a call. Every test page explains how to use it, what it can show, how it works and where its limits are.
Who runs this site
CheckYourDisplay is an independent site, started in September 2026. It exists for the reasons above: quick, trustworthy checks of a screen, speakers, a microphone or a camera, with a plain account of what a browser can and cannot measure. Questions, corrections and reports of a test that does not work on your device are welcome: see thecontact page.
How the tests work
Every test runs on your device with standard web technology. Display tests use the Fullscreen API and draw their patterns at your screen’s native resolution with CSS and the Canvas API, so no image is scaled or compressed, and some draw one canvas pixel per device pixel, so a 1-pixel line stays 1 pixel wide. The refresh rate estimate times the gaps between the frames the browser draws. Audio tests synthesize tones and noise with the Web Audio API and send them left or right with a stereo panner, with one channel’s waveform inverted, or onto discrete 5.1 or 7.1 channels where the browser reports that many outputs. The audio latency estimate schedules a click on the audio clock and lights a small cue when the browser expects that click to leave your output, so you can line the two up by eye and ear.
Microphone and camera tests ask for permission and use the stream only inside the page; the spectrum analyzer adds a Web Audio AnalyserNode that reads the level of each frequency band. Input tests read keyboard, pointer, touch and gamepad events as they happen, down to a pen’s pressure, tilt and twist, the raw movement a pointer lock reports, and the separate reports a browser groups into one event. Device tools read what the browser reports about your screen and its features, along with motion and orientation events from a device’s sensors, and ask the Vibration API for a buzz. The cleaning tools fill the screen with a plain field or a lock screen and ignore the input that reaches their own page while you wipe.
Testing is not diagnosis
A test shows you what your hardware does with a known pattern or sound; you judge the result. The same symptom can have several causes: a silent speaker can be a balance setting, a mono audio option, a cable or a fault. Results also depend on your settings, the light in the room and the browser. The tools are for basic testing and troubleshooting, not a professional measurement.
- No software can repair a dead pixel or permanent burn-in. The Stuck Pixel Fixer can sometimes free a pixel that is stuck on one color, with no guarantee.
- The audio tones check speakers and headphones. They are not a hearing test.
- The Speaker Cleaner’s tone may help push water droplets out of a phone speaker grille, with no guarantee. It cannot dry a phone, remove dust or repair water damage.
- If a test suggests a fault, check the manufacturer’s warranty and pixel policy for your device.
What a browser can and cannot measure
| Question | In a browser | To measure it exactly |
|---|---|---|
| Refresh rate | Estimated from how often the browser draws a frame. It can read low when the browser, battery saving or the system limits drawing. | The exact value is in your display settings. |
| Dead and stuck pixels | Shown, not measured: the page fills the screen with colors and you spot the faults. | Nothing else needed. |
| Color accuracy, white point, gamut | Cannot be measured. Patterns only help you see tint and banding. | A hardware colorimeter. |
| Brightness in nits, contrast ratio | Cannot be measured. Patterns show relative steps you can see. | A luminance meter or colorimeter. |
| Blooming, local dimming zones | Shown, not measured: bright shapes on black reveal halos. The number of dimming zones cannot be read. | A luminance meter, and the display’s specifications for the zone count. |
| Response time, input lag | Cannot be measured in milliseconds. Moving patterns show ghosting and blur you can see. | A photodiode or a high-speed camera. |
| Flicker (PWM) frequency | Cannot be measured. Patterns and the phone camera method help you see flicker. | A light sensor and an oscilloscope. |
| HDR | What the browser reports it supports, which is not proof the screen shows HDR. | The display’s own HDR status and a colorimeter. |
| Screen resolution | Reported in CSS pixels, with the physical pixels calculated from the pixel ratio. | Your display settings show the native value. |
| Screen size in inches, PPI | Not known to a browser. The site estimates PPI from a diagonal you enter. | A ruler or the manufacturer’s specification. |
| Speaker frequency response, loudness | Cannot be measured. Tones and sweeps let you listen for problems. | A calibrated measurement microphone. |
| Audio latency | An estimate only: you line up a scheduled click with a visual cue by eye and ear, relative to this screen. | A microphone and a light sensor recorded together on an oscilloscope. |
| Microphone level | The relative level (dBFS) of the signal the browser receives, after its own processing. | A sound level meter for dB SPL. |
| Microphone spectrum | The level of each frequency band in relative dBFS, not sound pressure, and it moves with the input volume. | A calibrated measurement microphone and analyzer. |
| Webcam resolution and frame rate | What the camera delivers to the browser, which can be less than its photo resolution. | The camera’s own software for its other modes. |
| Keys, buttons, touches, controller input | Every event the browser receives. Some keys, such as Fn, never reach a web page. | The device maker’s software for anything below the browser. |
| Mouse polling rate | An estimate of the reports the browser receives per second, which can read below the USB rate. | The mouse maker’s software shows the setting. |
| Mouse DPI | An estimate from moving the mouse a measured distance, with raw input. | The mouse maker’s specifications or software. |
| Pen pressure | Reported as a value from 0 to 1, so the pen’s own hardware pressure levels cannot be read. | The pen or tablet maker’s specifications and driver. |
| Keyboard latency | Not measured on this site. | The device maker’s software. |
| Motion and orientation sensors | The browser’s processed readings, which the system may filter, round and rate-limit. Nothing is calibrated. | A calibrated reference sensor, or the device maker’s own diagnostics. |
| Vibration strength | Only whether the browser accepted the request. Whether the device buzzed, and how hard, is not measured. | A vibration meter or an accelerometer against the case. |
How we write and check guides
Guides are written and checked by CheckYourDisplay. Each guide links the official pages its steps and claims come from, such as Microsoft, Apple, Google and Mozilla help pages, standards bodies and manufacturers’ own policies, and shows the date it was last checked against them.
Found a mistake or an out-of-date step? Email contact@checkyourdisplay.com with the page and what has changed.
Privacy
Your results, audio and video never leave your device. The site sets no cookies for visitors and keeps only anonymous, first-party usage statistics, such as which pages were opened and whether a test was started. The privacy page lists exactly what they contain.
Where to start
Checking a monitor? Start with the display tests. For sound, the audio tests; before a call, themicrophone and camera checks. The guides walk through common jobs step by step, such as testing a new monitor.
Last updated: October 6, 2026