How the test works
Press Start camera and the browser asks for permission; the camera does not turn on before you agree. The preview then appears in the dark panel, and the chip over it reports what the camera delivers: the frame size in pixels and the frame rate counted over the last second. The list above the buttons switches between cameras, for example the front and rear camera of a phone or a built-in and an external webcam; switching mid-run ends the current run and starts a new one on the chosen camera. Mirror flips the preview horizontally, which is the natural view for a front camera, and Snapshot saves the current frame as a PNG file to your device. The small button in the corner of the preview opens it fullscreen; Esc, the close button or a swipe down bring you back.
The frame rate is measured, not read from a label. The page counts every frame the browser presents from the camera and reports frames per second; during the run the chip shows the last second, and the result shows the average over the whole run. Because it depends on light, on the camera's mode and on how busy the computer is, the result is marked as approximate. A browser that cannot report presented frames shows the rate the camera itself declares instead of a count.
The stream is used only on this page. The video element shows it, the frame counter watches it, and the snapshot is drawn on a canvas inside the tab and downloaded to your device. Nothing is transmitted; the "Local by design" note on the side says exactly this.
What the result means
The card shows the average frame rate of the run and, underneath, the resolution with its common name (720p, 1080p), the camera's name and how long the preview ran. The numbers describe what the camera delivered under the conditions you tested in, and here is how to read them.
- 1280 × 720 at 30 fps is the working minimum for video calls; most built-in laptop cameras deliver exactly this.
- 1920 × 1080 at 30 fps is what external webcams sold as "Full HD" should reach in good light over a direct USB connection.
- A frame rate well below the camera's rating, for example 15 fps from a 30 fps camera, usually means low light or a power-saving mode; test again with a lamp facing you.
- A resolution below the camera's rating points to a USB bandwidth limit, another app holding the camera, or a browser cap on a phone.
Look at the picture as well as the numbers. Colour casts, a picture that pulses brighter and darker, or banding under artificial light are exposure and flicker issues, often fixable in the camera's own software by matching the power line frequency (50 Hz in Europe). A soft picture that no light improves is a dirty or scratched lens or a misaligned focus.
What to do if something is wrong
If the preview stays black, check the privacy slider or LED many webcams have, then the operating system's camera permission for the browser (Privacy settings on Windows, Privacy & Security on macOS, site permissions on phones), then whether another app, such as a video call left running, holds the camera. Only one app can use most webcams at a time. Try each device in the list; a laptop with a docking station may list a camera that is not connected. Then reload the page and start again.
If the resolution or the frame rate is lower than expected, connect the camera directly to a USB port on the computer rather than through a hub or a monitor, close other camera apps, and add light. On a phone, close other apps that used the camera recently. If the picture is upside down or rotated, the camera's own software or the operating system usually has a rotation setting; the browser shows the frames as delivered.
When to return or claim the warranty
A new webcam that is not detected on any port, delivers a resolution far below its rating in good light over a direct connection, or shows dead lines, stuck bright pixels or a permanent colour cast in the snapshot is defective and should be exchanged within the return window. Save a snapshot here showing the fault and note the resolution and frame rate from the result; they document the claim. A low frame rate in a dim room, a picture softer than a phone camera's, and the noise of a small sensor at night are limitations of the class of device, not defects, and are not grounds for a claim.
Frequently asked questions
Is the video streamed to a server?
No. The camera stream goes from the browser straight into the video element on this page and nowhere else. The frame rate is counted from the frames the browser presents, the resolution is read from the video element, and a snapshot is drawn on a canvas inside the tab and handed to you as a file. Nothing is transmitted; you can verify it in the browser's network panel while the preview runs.
The preview shows 640 × 480 but my camera is 1080p. Why?
The page asks for 1920 × 1080 as a preference and the browser negotiates the best mode the camera and the system allow. Some cameras only offer their full resolution over USB 3, some laptops cap the built-in camera when another app has it open, and browsers on phones may pick a lower mode to save power. Close other apps that use the camera, plug a USB camera directly into the computer rather than through a hub, and start the test again.
Why does the frame rate read 24 or 15 instead of 30?
Webcams lower their frame rate in dim light to let each frame collect more light, so 15 fps in an evening room is normal and rises to 30 with a lamp on. Some cameras are limited to 24 or 25 fps at their highest resolution. The value here is counted from presented frames over the whole run and is approximate: a busy computer or a battery-saving mode in the browser can shave a frame or two.
Should the preview be mirrored?
For a front camera, a mirrored preview feels natural because it behaves like a mirror when you move; that is why video call apps mirror your own view but send the unmirrored picture to others. For a rear camera or a document camera, turn the mirror off so text reads correctly. The snapshot follows the current mirror setting, so switch it off before photographing anything with writing on it.
The snapshot is dark or blurry although the preview looked fine.
A snapshot is one frame at full sensor resolution, while the preview is scaled down and smooths noise visually. Poor light produces grain and motion blur in single frames; add light from the front, hold still for a moment and try again. If the picture is soft everywhere, wipe the lens and check whether the camera has a focus ring or a privacy slider partly in the way.