Free tools / Screen test

Monitor & Screen Test

Check refresh rate, touch response, colour banding, backlight bleed and brightness uniformity on a laptop, monitor, phone or TV, all from the browser.

FreeRuns in your browserNothing uploaded

Estimated refresh rate

Counting

Frame time

Counting

Frames in 2 s

0

Keep this tab in front while it counts.

The browser draws at the rate the operating system gives it, and some browsers cap the figure, so treat the number as a guide. A screen rated higher than the reading usually needs its refresh rate set in the display settings first.

Runs on any screen this browser is on, including an external monitor or TV if you drag the window there first. For single dead or stuck pixels use the dead pixel test.

Full-screen tests need a click or tap to start. On iPhone the test covers the page instead, because iOS does not let web pages go full screen. The refresh rate figure is capped by the browser on some devices. Everything runs locally in your browser and nothing is uploaded.

How to use the screen test

1

Run the refresh rate check. It counts frames for two seconds and reports the rate the browser is drawing at. If a 120 Hz or 144 Hz screen reads 60, check the display settings, the cable and any battery saver mode, then press Run again.

2

Paint the touch canvas. On a touchscreen, draw with one finger, then several. The counter shows how many touch points the screen reports at once. Touch every cell in the grid to turn it green. A cell that will not turn green is a dead zone.

3

Step through the colour ramps. The screen fills with a smooth ramp from black to white, then red, green and blue. Click, tap or use the arrow keys to move on and Esc to leave. Look for visible steps or bands in what should be a smooth fade.

4

View black, grey and white in a dark room. Backlight bleed shows on the black screen as light leaking in from the edges or corners. Uneven brightness and dirty-screen effect show on the grey and white screens as patches, stripes or shadows.

What the results mean

Refresh rate reads lower than the panel. Browsers draw at the rate the operating system gives them, so a laptop set to 60 Hz to save battery will read 60 even on a 120 Hz panel. Some browsers also cap the figure. Check the display settings and the cable before treating it as a fault.

Fewer touch points than expected, or a dead cell. Most touchscreens report ten points. A cell that never turns green, or a stripe of them, is a dead zone in the digitiser. On a laptop that is a screen assembly fault, because the touch layer is bonded to the panel.

Banding in the ramps. Gentle steps in the greyscale ramp are common on 6-bit panels and can also come from a colour profile. Bands that sit as lines or blocks at fixed positions, or that shift and flicker, point to a failing panel or ribbon cable.

Backlight bleed. A soft glow along an edge or corner on the black screen is common on LCD panels and only matters when it is strong enough to notice in normal use. A bright spot that grows over time, or cloudiness across a whole area, is a panel problem.

Uneven grey or white. Darker corners, vertical stripes or a shadow where the panel is pressed by the case are uniformity faults. A small amount is normal. On a laptop, heavy patches or a shadow that follows the hinge line usually mean the panel is damaged.

When it is a screen replacement

A laptop panel with fixed bands, a dead touch strip, heavy bleed or a shadow that spreads is not going to recover, and settings will not hide it. We replace laptop screens for all the main brands and MacBook at our Kings Cross workshop, with a free diagnosis and an exact quote before any work, and we take screens by post from anywhere in the UK. Pair this page with the dead pixel test to check the same panel for single dead or stuck pixels, then see the laptop screen replacement page if the panel has failed.

Bands, bleed or a dead touch zone?

Laptop screen replacement in London for Dell, HP, Lenovo, ASUS, Acer, MSI, Microsoft Surface and MacBook. Free diagnosis, exact quote before any work, No Fix No Fee.

Laptop screen replacement Book a screen replacement

Open now, 24/7No Fix No Fee

Screen test: your questions answered

Why does the refresh rate test show 60 Hz on my 144 Hz monitor?−

The browser draws at the rate the operating system reports. Check that the monitor is set to its full rate in the display settings, that the cable supports it and that no battery saver or power mode has lowered it. Some browsers also cap the figure. Run the test again after each change.

Does the touch test work on a laptop without a touchscreen?+

No. It needs a screen that reports touch. On a laptop without one the panel says so and the other tests still work. A trackpad is not a touchscreen and is checked with the mouse tester instead.

Is a little banding or bleed normal?+

Yes. Most LCD panels show faint bleed on a black screen in a dark room, and cheaper panels show gentle steps in a greyscale ramp. It becomes a fault when you can see it in normal use, when it grows, or when it appears as fixed lines, blocks or a spreading patch.

Why does the test not go full screen on my iPhone?+

iOS Safari does not allow web pages to enter full screen, so the test covers the page instead. The browser bars stay visible, which is a limit of the phone rather than the test. Tap to move on and use the Exit button to leave.

Is this test safe for an OLED screen?+

Yes. The screens are shown briefly and are no different from normal use. Avoid leaving the white or grey screen up for a long time on an OLED panel.

More free testers

Dead pixel test Screen test Gamepad tester Keyboard tester Mouse tester Speaker and headphone test Click speed test All free tools Gaming hub All services

Screen past saving?
Laptop screens replaced at our Kings Cross workshop, open 24/7, or by post from anywhere in the UK.

Book a screen replacement Call 0800 955 0071