JS Tests
Free, instant browser tests for your monitor, mouse, and keyboard — measure FPS, refresh rate, polling rate, DPI, and more. No install, no login.
All JS Tests Tools
Browser-based tests for your monitor, mouse, keyboard, and reflexes
JS Tests is a collection of free, browser-based tools for checking your hardware — no downloads, no accounts, and nothing ever leaves your device. Whether you're tuning a new gaming monitor, diagnosing a flaky mouse, or benchmarking your reflexes, each test runs instantly and gives you clear, accurate readings.
Display & Monitor: Measure your real frame rate and refresh rate, hunt for dead or stuck pixels, check for backlight bleed, and see your exact screen size and resolution.
Mouse: Check your mouse's polling rate and true DPI, test every button and the scroll wheel, and diagnose scroll jitter or double-click misfires.
Keyboard & Typing: Test every key for dead or chattering switches, and measure your typing speed, key speed, and spacebar clicks.
Speed & Reflexes: Benchmark your reaction time, clicks per second, actions per minute, and input lag with simple timed tests.
Display & Monitor
Frame Rate Tester
Measure how many frames per second your browser is actually rendering in real time, with a live graph and min/avg/max readout.
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Refresh Rate Tester
Detect your monitor's true refresh rate (60Hz, 120Hz, 144Hz, 240Hz…) directly in the browser using the animation frame clock.
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Dead Pixel Tester
Flood your screen with full-screen solid colors to spot dead, stuck, and hot pixels, plus backlight bleed — cycle red, green, blue, white, black and more.
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Dead Pixel Fixer
Drag a patch of fast-flashing color noise over a stuck pixel to exercise it back to life — the browser-based pixel-repair method, no install required.
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Screen Bleeding Test
Fill your screen with pure black to reveal backlight bleed, corner glow, IPS glow, and clouding around the edges of an LCD panel. Best in a dark room.
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What Is My Screen Size?
Instantly see your screen resolution, browser viewport, device pixel ratio, aspect ratio, and color depth — detected live. Plus measure your screen's true physical size in inches with a quick credit-card calibration.
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Mouse Polling Rate Tester
Test your mouse's polling rate in hertz — how often it reports its position to your computer — with a live meter showing your current, peak, and average rate.
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Mouse Tester
Check that every button and the scroll wheel on your mouse works. Click left, right, middle, and side buttons to see them light up on a mouse diagram, scroll to test the wheel, and catch double-click misfires from a worn switch.
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Mouse Scroll Wheel Test
Diagnose scroll wheel jitter, reverse scrolling, and skipping. Scroll one direction for a timed run and get your scroll speed, up/down counts, reverse-jitter detection, and a wheel-health verdict.
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Mouse DPI Analyzer
Measure your mouse's real DPI in the browser. Enter your configured DPI and a distance, slide your mouse that far along a ruler, and get your true DPI, the pixel counts, and the deviation from the box claim.
Try it!Keyboard & Typing
Keyboard Tester
Press each key and watch it light up on a full virtual keyboard. Find dead, stuck, and chattering keys, check ghosting and key rollover, and see each key's code — with Windows and Mac layouts.
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Typing Speed Test
Test your typing speed in words per minute (WPM) and accuracy. Type the passage as fast as you can before the timer runs out, with live WPM, accuracy, a rank, and a speed-over-time graph. Pick 15, 30, 60, or 120 seconds.
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Keyboard Clicker
Measure your keyboard speed in keys per second (KPS). Press any key as fast as you can before the timer runs out — works as a spacebar counter too, with live KPS, a rank, and an over-time graph. Pick 1, 5, 10, 30, 60, or 100 seconds.
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Spacebar Clicker
See how many times you can hit the spacebar in clicks per second (CPS) — the spacebar challenge. Tap space as fast as you can before the timer runs out, with live CPS, a rank, a press counter, and an over-time graph. Pick 1 to 100 seconds.
Try it!Speed & Reflexes
CPS Test
Measure your click speed in clicks per second (CPS). Click as fast as you can before the timer runs out — pick 1, 5, 10, 30, 60, or 100 seconds, including the Kohi 10-second test.
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Right Click CPS Test
Measure how fast you can right-click in clicks per second (CPS). Same timed test as the CPS test, but it counts only right mouse button clicks — pick 1 to 100 seconds.
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APM Test
Measure your actions per minute with a reflex grid — hit each tile the moment it lights up. The RTS benchmark for mechanical speed, with live, peak, and average APM plus accuracy across 3×3, 4×4, and 5×5 grids.
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Reaction Time Test
Measure how fast your reflexes are in milliseconds. Wait for the screen to turn green, then click as fast as you can — five attempts are averaged, with your last, average, and best times and a rank against the human average.
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Input Lag Tester
Test the combined latency of your display, input device, and reaction time with a simple click-on-change test.
Try it!Why Choose Our JS Tests?
Private & Local
Every test runs entirely in your browser. Nothing is uploaded, tracked, or stored.
Instant Results
No install and no sign-up. Open a test and get live readings immediately.
Any Device
Works on desktop, laptop, tablet, and phone across all modern browsers.
Accurate & Free
Precise readings from native browser APIs — and every tool is 100% free.
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