Screen diagnostics

Free Open Source Monitor Color Test

Cycle through 14 color panels to check color accuracy, gradient banding, backlight uniformity, and contrast.

Pure Black 1/14

Jump to a test:

Tip: Press F to go fullscreen, / Space for next, for previous. Click anywhere on the panel to advance. For accurate results, dim room lighting and let your monitor warm up for 15 minutes.

14 color tests
Solids, gradients, ramps & patterns
Fullscreen mode
Edge-to-edge panel inspection
Works on any display
Monitor, laptop, tablet or TV
No download needed
Runs entirely in your browser

What to Look for During the Color Test

Each test panel targets a specific display defect. Here is what to watch for on each one.

Pure Black

Look for grey or light patches, especially near the edges and corners. Bright spots indicate backlight bleed — light leaking through the LCD panel where it should be blocked.

Pure White

Check for uneven tinting across the panel. Yellow or pink patches in corners or at the edges suggest poor backlighting or failing LEDs. A uniform white is expected on a healthy display.

Red / Green / Blue

Look for uneven brightness across the panel (called uniformity). Areas that appear brighter or darker than the rest suggest uneven backlighting or local dimming issues.

Gradient Tests

Watch for visible bands or steps instead of smooth transitions — this is called color banding. It indicates a 6-bit panel that uses dithering to simulate colors it cannot display natively.

What Is Color Banding?

Color banding occurs when a monitor cannot display smooth gradients, producing visible steps or stripes instead of a continuous transition.

6-bit TN

Budget panels

6-bit TN panels display only 262,144 true colors and use dithering to simulate more. Gradient tests almost always show visible banding on these displays.

8-bit IPS/VA

Mid-range panels

8-bit IPS and VA panels display 16.7 million true colors. Gradients usually appear smooth, though slight banding can still appear on low-quality units in very dark tones.

10-bit HDR

Professional / HDR panels

10-bit HDR panels display over 1 billion colors. Gradients are always perfectly smooth. Color banding on these displays would indicate a driver or GPU output issue, not a panel defect.

Backlight Bleed vs IPS Glow

Both appear during the Pure Black test but have different causes and different implications for your display.

Backlight Bleed

Bright white or light-coloured patches at the edges or corners of a pure black screen. Caused by physical gaps in the panel assembly that allow backlight to leak through. Severe bleed may qualify for a warranty replacement.

IPS Glow

A silver or golden shimmer visible only at extreme viewing angles near the corners of an IPS display. This is a normal characteristic of the IPS panel technology, not a manufacturing defect, and is not covered by warranties.

How to Test

Select the Pure Black test panel and view it in a dimly lit or dark room. Backlight bleed is visible head-on; IPS glow appears only when you tilt or look at the screen from the side at a shallow angle.

Warranty Claim

Document bleed patches in a photo taken head-on in a dark room. Most manufacturers consider bleed a defect only if it is visible under normal use conditions. Extreme bleed that is distracting during everyday use is typically covered.

Monitor Calibration After This Test

If colors look inaccurate, these steps will help you improve display quality.

01

Use your monitor's OSD

Access the On-Screen Display menu (usually a button on the monitor bezel). Adjust color temperature (try 6500K for standard use), brightness, and contrast to match what you see in the test panels.

02

Windows / macOS calibration

Both operating systems include a built-in display calibration wizard. On Windows, search for "Calibrate display color." On macOS, go to System Settings → Displays → Color → Calibrate.

03

Hardware colorimeter

For professional or color-critical work, use a hardware colorimeter such as a Datacolor Spyder or X-Rite i1Display. These devices measure the actual light output and create a custom ICC color profile for your specific panel.

Also useful: Dead Pixel Test — check for dead and stuck pixels using fullscreen solid colors.  |  Refresh Rate Test — measure your monitor's actual refresh rate.

More testing tools

Explore the full suite for keyboard, mouse, audio, and utilities.

Language support: All major tools are available in 9 languages - English plus Arabic, Russian, Spanish, French, Portuguese, Japanese, German, and Korean. Select your language from the header menu to switch.

Keyboard
Keyboard Tester

Test keyboard functionality, detect ghosting, measure latency, check for stuck keys

Test your keyboard 5.0 (4)
Keyboard
Arabic Keyboard Tester

Test Arabic keyboard layout and key response in an Arabic-first interface

Test Arabic layout Rate
Keyboard
Typing Speed Test

Measure WPM, accuracy, and typing consistency

Check typing speed 5.0 (1)
Keyboard
Latency Checker

Test device and input latency in your browser

Measure latency 5.0 (1)
Keyboard
Spacebar Speed Test

Count how many spacebar presses you can make in 5, 10, or 30 seconds

Test your spacebar 5.0 (1)
Keyboard
Key Repeat Rate Tester

Measure your keyboard key repeat rate (Hz) and initial delay (ms) in your browser

Test repeat rate 5.0 (1)
Keyboard
Typing Rhythm Fingerprint

Visualize your inter-keystroke timing patterns and get a rhythm consistency score

Analyze rhythm 5.0 (1)
Keyboard
Keyboard Switch Sound Analyzer

Classify your mechanical keyboard switches as linear, tactile, or clicky using mic FFT analysis

Analyze sound 5.0 (1)
Keyboard
Keyboard Chatter Detector

Find keys that register twice from a single press with configurable threshold and per-key stats

Detect chatter 5.0 (1)
Keyboard
Keyboard Polling Rate Test

Estimate keyboard Hz using browser auto-repeat timing measurement

Test polling rate 5.0 (1)
Keyboard
Keyboard Shortcut Identifier

Press any key combination and instantly see what it does on Windows, macOS and Linux

Try a shortcut 5.0 (1)
Mouse
Mouse Tester

Check mouse buttons, scroll wheel, cursor movement, and responsiveness

Test your mouse 5.0 (1)
Mouse
Mouse Speed Tester

Measure your click speed (CPM or CPS) with timed tests

Check click speed 4.0 (4)
Mouse
Mouse Sensitivity / DPI

Test DPI, sensitivity, and tracking accuracy

Test DPI settings 5.0 (1)
Mouse
Mouse Trail

Visualize mouse movement trails and precision

View mouse trails 5.0 (1)
Mouse
Ghost Click Detector

Detect unintended or phantom clicks

Detect ghost clicks 5.0 (1)
Mouse
Mouse Polling Rate Test

Check if your gaming mouse runs at 125Hz, 500Hz, 1000Hz or higher

Test polling rate 5.0 (1)
Mouse
Mouse LOD Tester

Measure your gaming mouse lift-off distance to optimize sensor performance

Test LOD 5.0 (1)
Mouse
Mouse Accuracy Test

Aim trainer benchmark — measure hit percentage, average pixel error, and reaction time per target

Test your aim 5.0 (2)
Mouse
Mouse Drag Click Test

Measure drag-click CPS, peak burst rate, and total clicks with live timeline graph

Test drag clicks 5.0 (1)
Mouse
Right Click CPS Test

Measure right-mouse-button CPS with browser context menu suppressed

Test right CPS 5.0 (1)
Mouse
Mouse DPI Calculator

Measure true mouse DPI by dragging a known distance or entering pixel and inch values manually

Measure DPI 5.0 (1)
Mouse
eDPI Calculator

Calculate effective DPI (DPI x sensitivity) and cm/360 for CS2, Valorant, Apex and other FPS games

Calculate eDPI 5.0 (1)
Mouse
Mouse Drift Test

Detect idle cursor drift and sensor jitter with a 10s-3min pointer-event sampler and pass/fail verdict

Test drift 5.0 (1)
Mouse
Mouse Acceleration Test

Compare slow vs fast swipe pixels to catch Windows pointer acceleration or firmware-level sensor acceleration

Test acceleration 5.0 (1)
Mouse
Mouse Spin Test

Counts full 360° mouse rotations over 15/30/60 s with peak spins-per-second and direction indicator

Start spinning 5.0 (1)
Display
Screen Tester

Detect dead, stuck, or hot pixels on screens

Test your screen Rate
Display
Monitor Refresh Rate Test

Detect if your display runs at 60Hz, 144Hz, 240Hz or higher

Test refresh rate 5.0 (1)
Display
Monitor Color Test

Check color accuracy, gradient banding and backlight uniformity

Test colors 5.0 (1)
Display
Backlight Bleed Test

Check your LCD monitor for backlight bleed, IPS glow, and clouding

Test for bleed Rate
Display
Touch Screen Test

Test for dead zones, ghost touches and multi-touch on phone or tablet

Test touch screen Rate
Display
PWM Flicker Test

Check if your monitor uses PWM backlight dimming that can cause eye strain

Test for flicker 5.0 (1)
Display
Monitor Gamma Test

Visual gamma calibration check using stripe-blend pattern, target sRGB 2.2

Test gamma Rate
Display
Monitor Ghosting Test

Detect pixel response time issues with adjustable-speed moving box on color backgrounds

Test ghosting Rate
Display
Black Level Test

Check shadow detail with 32 near-black patches, detect crushed blacks

Test black level 4.5 (2)
Display
White Level Test

Check highlight detail with 32 near-white patches, detect clipped whites

Test white level Rate
Display
Brightness Test

11-step grayscale ladder to verify brightness, contrast, and gamma calibration

Test brightness Rate
Display
Contrast Test

Checkerboard vs 50% gray squint test for contrast and gamma calibration

Test contrast 5.0 (2)
Display
PPI Calculator

Compute pixels per inch, dot pitch, aspect ratio and megapixels for any display from resolution + diagonal

Calculate PPI 5.0 (1)
Display
Aspect Ratio Calculator

Type any two of width, height, or ratio. Auto-simplifies to lowest integer terms and renders a live preview

Open calculator 5.0 (1)
Display
Screen Size Calculator

Compute diagonal, width, height and visible area from aspect ratio plus any one dimension — in inches and cm

Calculate size Rate
Display
Viewing Distance Calculator

Optimal TV/monitor viewing distance by THX (36° FoV), SMPTE (30° FoV), and the 4K/8K resolving-limit

Find distance Rate
Display
FPS Test

Live frame rate measurement with avg/min/max/1%-low plus 60/120/144/165/240Hz detection

Start FPS test Rate
Display
Screen Resolution Test

Live readout of screen resolution, native pixels, device pixel ratio, color depth, and gamut

See resolution Rate
Display
OLED Burn-In Test

Cycle 8 solid colors, fine checkerboard, and scrolling refresher fullscreen to detect OLED burn-in

Test burn-in Rate
Display
Color Range Test

Detect Full RGB (0-255) vs Limited (16-235) via near-black and near-white patch grids

Test RGB range 5.0 (1)
Display
Screen Uniformity Test

Fullscreen gray/black/white/RGB at any brightness to spot clouding, IPS glow, and backlight bleed

Test uniformity Rate
Display
Frame Skipping Test

Detects dropped or skipped frames at your refresh rate with rAF timestamp analysis and a visual reference bar

Detect skipped frames Rate
Display
Monitor Sharpness Test

Lagom-style 1px pixel grid, multi-size text samples, color-fringing blocks, and an RGB sub-pixel ruler to evaluate display sharpness

Test sharpness Rate
Camera
Webcam Tester

Check webcam quality, resolution, and snapshots

Test your webcam 5.0 (1)
Camera
Webcam Mirror

Use your webcam as a real-time virtual mirror with horizontal flip, brightness/contrast, grid, and snapshot

Open mirror Rate
Audio
Mic Tester

Verify microphone input and audio levels

Test your microphone Rate
Audio
Headphone / Speaker Tester

Test stereo channels and sound output

Test audio output Rate
Audio
Decibel Meter

Live dB SPL measurement using your microphone with peak and rolling average

Open meter 1.0 (1)
Audio
Sound Test

Speaker and headphone channel verifier plus 100 Hz → 10 kHz frequency sweep

Test sound 5.0 (1)
Audio
Bass Test

Subwoofer and low-frequency sweep (20 Hz → 200 Hz) with ISO 1/3-octave bass presets

Test bass Rate
Audio
Frequency Response Test

Full-range 20 Hz → 20 kHz log sweep with hearing-limit logging and manual tone slider

Start hearing test Rate
Audio
Auditory Reaction Time Test

Measure how fast you respond to a sound cue in milliseconds using the Web Audio API

Start sound test Rate
Audio
Surround Sound Test

5.1 and 7.1 channel walk-around to verify speaker wiring, with stereo panning fallback for headphones

Test surround Rate
Audio
Pitch Detector

Sing or play any note. Get live Hz, nearest note (C0-C8), octave, and cents off perfect pitch

Open pitch detector Rate
Audio
Hearing Age Test

Mosquito tone hearing test - 12 frequencies from 8 kHz to 22 kHz to estimate your hearing age

Test hearing age Rate
Utility
OCR Tool

Extract text from images quickly

Extract text now 5.0 (1)
Utility
QR Code Reader

Scan QR codes with camera or image upload

Scan QR codes Rate
Utility
QR Code Generator

Create custom QR codes instantly

Create QR code Rate
Utility
Password Generator

Create strong, secure passwords instantly

Generate password Rate
Utility
WhatsApp Link Generator

Create clickable WhatsApp chat links

Generate chat link Rate
Utility
WhatsApp Brand Links

Create branded WhatsApp links and QR codes

Create brand link Rate
Utility
WhatsApp Chat Analyzer

Deep AI tone report for chats and text

Analyze chat tone Rate
Utility
Lucky Wheel

Spin a random picker wheel for names, teams, prizes, and quick choices

Spin the wheel Rate
Utility
All Tools

Browse all hardware testing tools in one place

View all tools Rate
Utility
WebRTC Leak Test

Detect IP address leaks through your browser even when using a VPN, IPv4 + IPv6 + local

Check IP leak Rate
Utility
Accelerometer Test

Live X/Y/Z acceleration readout in m/s² with tilt ball, shake counter, and peak-g tracking

Test motion sensor 2.0 (1)
Utility
Gyroscope Test

Live alpha/beta/gamma rotation readout with 3D cube, compass ring, and calibrate-to-zero

Test rotation sensor 5.0 (1)
Utility
Vibration Test

Phone haptics patterns (Vibration API) and gamepad rumble per-motor intensity in one tool

Test vibration Rate
Utility
CPU Stress Test

Multi-threaded WebWorker SHA-256 busy loop to load every logical core and report ops per second

Stress the CPU Rate
Utility
AI GPU Test

Check WebGPU, WebGL2, WebNN and browser AI readiness with a safe matrix compute benchmark

Test AI GPU readiness Rate
Utility
GPU Stress Test

WebGL2 Mandelbrot fragment shader benchmark that pushes any GPU and reports FPS, minimum FPS, and software-rendering fallback

Stress the GPU Rate
Utility
Memory Test

Browser heap monitor with live performance.memory readout, allocation stressor, and safe auto-abort

Open memory test Rate
Utility
RAM Latency Calculator

Convert CAS latency (CL) and memory speed (MT/s) to real nanoseconds, compare DDR4 vs DDR5 kits side by side

Calculate RAM latency Rate
Utility
Bandwidth Calculator

Solve for transfer time, file size, or required speed - handles bits vs bytes math automatically

Open bandwidth calc Rate
Utility
Download Time Calculator

Estimate download duration for games, movies, and backups at your connection speed with realistic overhead

Estimate download time Rate
Utility
RAID Calculator

Usable capacity and fault tolerance for RAID 0/1/5/6/10/50/60 with side-by-side level comparison

Calculate RAID 5.0 (1)
Utility
Online Ruler

Actual-size cm and inch ruler on screen with credit-card calibration (ISO ID-1) and DPI presets

Open ruler Rate
Utility
AI Assistant

Chat with the site's AI helper — it picks the right hardware test, links you to it, and explains the result in 9 languages

Open AI chat 5.0 (1)
Gaming
Gamepad Tester

Test PS5, Xbox, Switch and PC controller buttons, stick drift and triggers

Test controller 5.0 (1)
Gaming
Reaction Time Test

Measure how fast you react with a browser-based millisecond reflex test

Test reaction time 5.0 (1)
Gaming
FoV Calculator

Convert field of view across aspect ratios and games with presets for CS2, Valorant, Apex, CoD and Fortnite

Convert FoV Rate
Gaming
Crosshair Generator

Design a custom crosshair with live preview, PNG export, CS2 console command, and Valorant settings values

Open generator Rate
Gaming
APM Test

Actions-per-minute counter for RTS & MOBA players — live APM, peak, and session average

Measure APM Rate
Gaming
Gamertag Generator

Random gamer names across 6 styles with length limits for Xbox, PSN, Steam, and Discord

Generate names Rate
Gaming
Guild Name Generator

Random MMO guild and clan names across 6 themes and 5 templates, with WoW/FFXIV/Destiny length limits

Generate guild names Rate
Gaming
TTK Calculator

Time-to-kill math for FPS games with body vs head comparison, armor handling, and CS2/Valorant/Apex/CoD presets

Calculate TTK Rate
Gaming
Minecraft Circle Generator

Pixel circle, filled disc, thick ring, and 3D sphere layer plotter for Minecraft builders, radius 1-256

Plot a circle Rate

Windows app

KeyboardTester.click is available from Microsoft Store

Install the official Windows app shortcut, or keep using the same free testing tools in your browser.

Download from Microsoft Store Download from Microsoft Store