Webcam test: check your camera

How it is calculated

Before a video job interview, after buying a new webcam or when Teams only shows a black picture: this webcam test shows at once whether the camera works – and which resolution and frame rate it really delivers in the browser. It uses the same interface as video calls in the browser.

How it works

1. Click “Test camera” and choose Allow in the browser prompt.
2. The live picture appears. Below it you see the delivered resolution, the frame rate and – if the browser reveals it – the camera’s highest resolution.
3. Under “Requested resolution”, ask for 720p, 1080p or 4K. The test shows what the camera actually delivers in response.
4. Several cameras (e.g. built-in and USB, or front and rear camera on a phone)? Choose the one you want at the top.
5. “Take photo” saves a still image as PNG or JPG.
6. “Turn camera off” ends access and the indicator light goes out. Leaving the page does this automatically.

What the values mean

• Delivered resolution: width × height in pixels that actually reach the browser, with its short name (720p, 1080p, 4K) and aspect ratio. This can be less than the box promises – for instance because the browser picks a smaller default size when nothing is requested, or because the camera offers its top resolution only at a low frame rate.
• Frame rate reported is the value camera and browser agreed on. Frame rate measured counts how many frames per second really arrive. If the measured value is clearly lower, the light is usually to blame: in the dark many webcams expose longer and therefore manage fewer frames.
• Camera supports up to: the highest resolution the camera reports to the browser. Not every browser reveals this; then it says “not reported by the browser”.
• Mirror only flips the display, the way you see yourself in a mirror. People in a call see you unmirrored. With mirroring on, the photo is saved mirrored as well.

Why “Automatic” often shows only 640 × 480

If a page does not request a specific size, Chrome and Edge often choose a small default resolution – even with a Full HD camera. Video call apps specifically ask for more. So pick a level: the browser then uses the closest setting the camera offers. The request is a wish, not a requirement – the picture appears even if the camera cannot reach that level, and the test tells you what arrives instead. That is how the W3C standard Media Capture and Streams (current W3C version, 2026) defines “ideal” constraints: the browser picks the setting closest to the request.

Resolution levels at a glance

The short name always follows the shorter side, so a portrait picture of 720 × 1280 counts as 720p.

Worked example: what does the camera really deliver?

1. You choose “1080p Full HD”. The browser asks for 1920 × 1080 as an ideal value.
2. The camera answers with 1920 × 1080. Megapixels: 1920 × 1080 = 2,073,600 pixels ÷ 1,000,000 = 2.07 → shown as 2.1 MP. Aspect ratio: 1920 ÷ 1080 = 1.78 = 16:9.
3. Frame rate measured: the test takes the time stamps of consecutive frames. 16 frames spanning 1,000 ms give (16 − 1) × 1,000 ÷ 1,000 = 15 fps.
4. Frame rate reported says 30 fps, measured shows 15 fps: the camera is exposing longer, almost always because of poor light. Turn on a lamp in front of you and the measured value climbs back towards 30 (31 frames in 1,000 ms = 30 fps).

Common webcam test mistakes

• Judging the camera on “Automatic”: 640 × 480 there is the browser’s default, not the camera’s limit. Request 1080p or use “Try all resolutions”.
• Trusting the megapixels on the box: that figure often applies to photos. What counts for calls is the video resolution the test shows.
• Testing in the dark: low light lowers the frame rate on many webcams and adds noise. Test with the light you will use in the call – a white screen on a second device works as a fill light.
• Leaving Teams or Zoom open: many webcams serve only one app at a time; the test then shows a black or “busy” picture.
• Worrying about the mirrored preview: mirroring only affects your own view. The other side sees you the right way round.

Camera not working? Troubleshooting

• Windows 11: Settings → Privacy & security → Camera: turn on “Camera access” and “Let desktop apps access your camera”. Many laptops have a camera key or a privacy shutter in front of the lens.
• macOS: System Settings → Privacy & Security → Camera: enable your browser, then restart it.
• Android: In Chrome, tap the icon on the left of the address bar → Permissions → allow Camera; otherwise Settings → Apps → Chrome → Permissions → Camera. From Android 12 on, check that the “Camera access” toggle in Quick Settings is on.
• iPhone/iPad: Settings → Safari → Camera: set to “Ask” or “Allow” (from iOS 18: Settings → Apps → Safari).
• “Busy” or black picture: often another app is already using the camera (Teams, Zoom, Skype, the Camera app). Many webcams allow only one user at a time – close the other app and start the test again.
• Camera missing from the list: try another USB port, directly on the computer rather than a hub. In Windows Device Manager, check under “Cameras” whether the device is disabled.

Honest limits

The test shows what the browser receives. Manufacturer software may use other resolutions and frame rates with the same camera. Image quality (sharpness, colour accuracy, noise) is for your eyes to judge – that is what the live picture and the photo function are for. A new resolution level briefly restarts the camera; a short flicker is normal.

Privacy

The camera picture is only shown on your screen. Nothing is uploaded or stored; photos are created in your browser and only end up on your device if you download them. The page only works over https because browsers do not allow camera access otherwise.

Before a call, check your sound as well: the mic test shows your input level, and the online mirror gives you a large, distraction-free view of yourself. To record a tutorial with camera and screen, use the online screen recorder.

Megapixels, brightness, sharpness and all resolutions

• Megapixels: width × height of the delivered picture divided by one million – 1920 × 1080 is 2.1 MP, 1280 × 720 is 0.9 MP. The figure on the box often applies to photos only, not to the video picture.
• Brightness: the average of all pixels from 0% (black) to 100% (white). Below 25% the picture looks too dark – it gets noisy and the frame rate often drops because the camera exposes for longer. Above 75% highlights may blow out, for example with a window behind you.
• Sharpness index: measures how much neighbouring pixels differ (variance of the Laplacian). It is not a standardised measure and depends on the scene. It is useful for comparing an unchanged picture: clean the lens, turn the focus ring or switch on a light – if the number rises, the picture is sharper.
• Try all resolutions: requests 480p, 720p, 1080p, 1440p and 4K one after another and lists what the camera really delivers each time, including the frame rate. No new permission is needed; afterwards your chosen level applies again.

Frequently asked questions

Sources and legal basis

• MDN Web Docs – MediaDevices.getUserMedia()
• MDN Web Docs – MediaStreamTrack.getSettings()
• W3C – Media Capture and Streams

As of: 5 October 2026 · Editorial policy