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60+ Instruments
SCREEN REFRESH RATE INSPECTOR
Screen Refresh Rate Test
Thought your 144Hz, 240Hz, or 360Hz gaming monitor was stuck at 60Hz? Measure your screen's true physical refresh rate, microsecond frame pacing jitter, and mobile ProMotion LTPO dynamic scaling instantly in your browser.
WARNING: PHOTOSENSITIVE SEIZURE & FLICKER HAZARD
A small percentage of individuals may experience epileptic seizures or photosensitive reactions when exposed to flashing lights, high-contrast strobing, or rapidly moving visual patterns. In compliance with WCAG 2.1 Success Criterion 2.3.1 (Three Flashes or Below Threshold), Display Test Online limits default strobing animations. However, dynamic visual tests inherently involve rapid refresh intervals.
Discontinue use immediately and consult a physician if you experience dizziness, altered vision, twitching, loss of awareness, or disorientation while running tests.
QUICK START TEST GUIDE
Screen Refresh Rate & Frame Pacing Guide
How to perform this test:
Allow the real-time Hz counter to measure your screen's frame rate for 3 seconds.
Observe the 4 side-by-side moving reticles (1x, 1/2x, 1/4x, 1/8x) to inspect motion blur and overdrive ghosting.
If using a camera/phone to photograph motion blur, click '📷 Camera Pursuit Grid' to enable alignment lines.
Click 'START FULLSCREEN TEST' when ready for uninterrupted full-screen frame pacing diagnostics.
* Note: Fullscreen mode will only activate when you explicitly click 'Start Fullscreen Test'. You can press ESC at any time to exit.
TV users can navigate with D-Pad & Remote arrow keys
ISO 9241-307 & W3C Frame Pacing Telemetry Standards
1. Microsecond Precision
Measures exact frame presentation intervals using sub-millisecond browser compositor timestamps rather than standard rounded integer counters.
2. Mobile LTPO / ProMotion
Evaluates dynamic variable refresh rate scaling, detecting energy-saving idle drops down to 10Hz and touch-boosted 120Hz gaming performance.
3. Multi-Rate Pursuit
Displays side-by-side 1x, 1/2x, 1/4x, and 1/8x motion sweep reticles for evaluating sample-and-hold display motion blur and tracking clarity.
Technical FAQs & Helpful Content
Frequently Asked Questions
Everything you need to know about this diagnostic instrument, calibration procedures, and display technical standards.
01.How does the Screen Refresh Rate Test measure real hardware Hz?
Our engine uses W3C High-Resolution Time (performance.now()) microsecond hardware timestamps combined with requestAnimationFrame compositor callbacks to measure your display's true physical refresh rate and inter-frame pacing deltas.
02.How do I test dynamic ProMotion or LTPO refresh rates on iPhone, iPad, or Android?
On dynamic mobile displays (such as Apple ProMotion or Samsung LTPO), the screen drops to 10Hz–30Hz when idle to save battery. Swiping or touching the screen triggers maximum 120Hz boost mode, which our real-time LTPO inspector automatically measures.
03.Why does my 144Hz, 240Hz, 360Hz, or 540Hz monitor only show 60Hz?
If your high-refresh gaming monitor displays 60Hz, check your operating system display settings (Windows Display Settings -> Advanced Display Settings -> Choose Refresh Rate). Ensure you are using a DisplayPort 1.4/2.1 or HDMI 2.1 cable capable of high bandwidth.
04.What is inter-frame jitter and micro-stutter?
Inter-frame jitter (measured in milliseconds σ) quantifies variance in frame delivery timing. High jitter causes visual micro-stutter even when average FPS appears high.
05.Can I test high refresh rate screens in any web browser?
Yes, modern Chromium (Chrome, Edge, Brave), Firefox, and Safari support hardware-accelerated requestAnimationFrame callbacks up to 540Hz+. Ensure browser hardware acceleration is enabled in settings.
06.How does VSync, G-Sync, and FreeSync affect refresh rate test results?
Variable Refresh Rate (VRR) technologies like NVIDIA G-Sync and AMD FreeSync dynamically synchronize your monitor's refresh rate to the GPU frame dispatch rate. Disabling VSync during testing allows measuring uncapped browser compositor performance.
07.What is display motion blur and Pursuit Camera reticle testing?
Sample-and-hold display tech (LCD/OLED) causes motion blur as human eyes track moving objects. Our pursuit motion sweep reticles display side-by-side moving targets at 1x, 1/2x, and 1/4x speeds to evaluate panel response time and overdrive ghosting.
08.Why does my frame rate drop when switching web browser tabs?
Web browsers automatically throttle requestAnimationFrame callbacks for background or unfocused tabs to save CPU/GPU power and battery. Keep the test window focused for accurate hardware measurements.
09.Does a higher refresh rate reduce input latency in competitive gaming?
Yes. Higher refresh rates reduce visual frame delay (1000ms / 240Hz = 4.16ms vs 1000ms / 60Hz = 16.67ms). This gives competitive players a ~12.5ms click-to-photon advantage.
10.How do I enable 120Hz or 144Hz output on macOS or Windows laptops?
On macOS: System Settings -> Displays -> Refresh Rate -> Select 120Hz or ProMotion. On Windows: Settings -> System -> Display -> Advanced Display -> Select Refresh Rate.
Not sure which test to run next? Need troubleshooting advice?
Clean your monitor surface, disable ambient light sensors, and set your display to native resolution and refresh rate.
02
Execution
Enter full-screen mode (F11) and use the diagnostic suite controls to progress through the test patterns.
03
Evaluation
Observe anomalies from different viewing angles in a dark room. Reference our testing guides to interpret your results.
HARDWARE ARCHITECTURE
Panel Technology Breakdown
Professional IPS (In-Plane Switching)
Superior color accuracy and viewing angles. Used in reference monitors. Prone to minor 'IPS Glow' in dark environments.
Consumer IPS (Fast IPS / Nano IPS)
High refresh rates and good response times for gaming, but lower static contrast ratios compared to VA.
VA Panel (Vertical Alignment)
Excellent deep blacks and high contrast (3000:1+). Often used in curved displays. Can exhibit 'black smearing' in fast motion.
OLED (Organic LED) & QD-OLED
Self-lit pixels deliver true black, near-instant response times, and infinite contrast. Subject to Auto Brightness Limiting (ABL).
ENGINEERING ANALYSIS
Technical Deep Dive & Display Methodology
Our testing methodology aligns with VESA, SMPTE, and ISO standards for display metrology. This diagnostic tool utilizes raw web APIs (Canvas, WebGL, CSS Color Level 4) to ensure bit-perfect rendering, bypassing OS-level compression and scaling where possible.
Real-Time Telemetry
Microsecond Frame Stream
144Hz V-Sync
Current: 144 HzJitter σ: 0.12 ms
PASS
LTPO Variable Hz
Dynamic Mobile Scaling
120/120
Idle Rate10 Hz
Touch Boost120 Hz
Reticle Parameters
Motion Sweep Speed
Controls
960 px/s
Shortcuts
Keyboard Navigation
Hotkeys
F
Toggle Fullscreen
Space
Pause / Resume
1234
Select Speed Preset
TV users can navigate with D-Pad & Remote arrow keys
Frame Pacing Standards
ISO 9241-307 & W3C
ISO Pacing
Standard Citations
W3C High Resolution Timeperformance.now()
Sub-millisecond hardware timestamps for accurate frame interval delta measurement.
Monitor OSD Calibration
Ensure VSync or G-Sync is disabled in GPU settings for uncapped browser FPS testing.
Disable background tabs to prevent browser rAF throttling.
HARDWARE DIAGNOSTIC PASSPORT
SHA-256 SIGNED CALIBRATION RECEIPT
DISPLAY HEALTH INDEX
92/ 100
EXCELLENT HARDWARE STATUS
VSync & Pacing32/35
Color & Uniformity30/35
Digitizer & Touch30/30
Resolution3840 x 2160
Device Pixel Ratio2.0 (HiDPI)
Color Depth24-bit SDR
VSync Refresh144.0 Hz
Touch APIMulti-Touch (10pts)
OLED Burn-In RiskMINIMAL
RECEIPT SHA-256 SIGNATURE2026-07-22 00:30 UTC
a4f8b92c103e57f1
100% Anonymized & Signed: Submitting publishes your SHA-256 receipt, refresh telemetry, and defect counts to aid buyer panel lot verification. Zero personal data collected.