🟠 Live Hz + Grade + VRR Simulator

Monitor Refresh Rate Test

Check your screen's real refresh rate, frame consistency and stability grade — plus a motion clarity test and VRR/G-Sync simulator most other tools don't have.

Current Hz
0
Hz live
Average Hz
0
Hz
Min / Max
Hz
Stability Grade
run test first
🖥️ Refresh Rate Test Suite
Hz — detected via requestAnimationFrame

Keep this tab active and in focus. Reading stabilizes after ~2 seconds. For best accuracy, use fullscreen and confirm your OS display setting is already at max refresh rate.

Frame Time Consistency (last 150 frames) Stable Dropped frame (>20ms)
Avg Frame Time
— ms
Dropped Frames
0
Jitter (StdDev)
— ms
Total Frames
0
Test Duration
0.0s
Closest Standard
⚠️ Diagnostic Suggestions
    1x SPEED
    2x SPEED
    4x SPEED

    Watch the moving blocks. On a high refresh-rate screen, edges stay crisp even at 4x speed. On 60Hz, expect visible ghosting and motion blur — especially on the fastest block.

    Fixed Refresh Rate (simulated tearing risk)

    Frame delivery timed to a rigid interval. When the GPU can't keep up, frames arrive late and either tear or stall — visualized here as irregular red gaps.

    Variable Refresh Rate (G-Sync / FreeSync style)

    The display refresh window stretches to match each frame as it's ready — shown as smoothly adapting green bars instead of rigid, missed intervals.

    Also test your keyboard! Check key response time, scan rate and all 104 keys.

    ⌨️ Keyboard Tester →

    Also test your mouse! Check polling rate up to 8000Hz, click latency and heatmap.

    🖱 Mouse Rate Test →

    What Is Monitor Refresh Rate?

    Refresh rate (Hz) is how many times per second your display redraws the image on screen, determined by the panel hardware. A 60Hz monitor refreshes 60 times per second (16.67ms per frame); a 144Hz monitor refreshes every 6.94ms. Higher refresh rate means smoother motion and lower perceived input lag.

    How This Tool Measures Your Refresh Rate

    The browser can't read your monitor's EDID directly, so this test uses requestAnimationFrame() — a callback the browser fires in sync with your display's vertical refresh. By timing the gap between consecutive callbacks over a rolling window, we calculate a live Hz reading, then track the average, min, max, and — uniquely — a stability grade based on how consistent your frame timing actually is, not just the peak number.

    Stability Grade formula: we measure what percentage of frames land within ±15% of your median frame interval. 95%+ consistent frames = Grade A. Below 60% = Grade F, meaning your refresh rate number may look right on average but is unstable in practice (often caused by background load, power-saving mode, or a mismatched cable standard).

    Why This Goes Beyond a Basic Hz Checker

    Most refresh rate testers online just show one live number. This tool adds three things you won't usually find together: a frame-time consistency chart that flags dropped frames individually, a 3-speed motion clarity test to see ghosting with your own eyes, and a VRR simulator that visually explains why G-Sync/FreeSync smooths out frame-rate fluctuations that a fixed refresh rate can't handle.

    Refresh RateFrame IntervalBest ForRating
    60 Hz16.67 msOffice, web browsing, videoFine
    75–90 Hz11.1–13.3 msCasual gaming, smoother scrollingGood
    120–144 Hz6.9–8.3 msMainstream competitive gamingGreat
    240 Hz4.17 msEsports / professional playElite
    360 Hz+<2.8 msTop-tier competitive FPSPro

    Getting an Accurate Reading

    ⚙️
    System Settings
    Windows may default to 60Hz even on a 144Hz panel. Check Settings → Display → Advanced Display and set it to max.
    🔌
    Cable Standard
    HDMI 1.4 caps at 1080p@120Hz. For 144Hz+ at higher resolutions, use DisplayPort 1.2+ or HDMI 2.0+.
    🔋
    Power Mode
    Laptop battery-saver modes silently cap refresh rate to 60Hz. Switch to high-performance mode before testing.
    🧩
    Hardware Acceleration
    If disabled in your browser, frame delivery can get locked to 60Hz regardless of your panel's real capability.

    Frequently Asked Questions

    Why does it show 60Hz when my monitor is 144Hz?
    Most common causes: your OS display setting hasn't been switched from the 60Hz default, you're using a cable that can't carry the full bandwidth, browser hardware acceleration is off, or your laptop is in a power-saving mode.
    How accurate is a browser-based refresh rate test?
    requestAnimationFrame is tied to your display's vsync, so under normal conditions readings are accurate to within ±1–2Hz. Background tabs, high CPU load, or OS-level frame pacing can cause temporary dips — which is exactly what the stability grade and frame-time chart are designed to surface.
    What does the Stability Grade actually measure?
    It's the percentage of frames that land within ±15% of your session's median frame interval. A high average Hz with a low grade usually means your setup is technically capable but not consistently hitting that rate — worth investigating before you trust the number on a spec sheet.
    What's the difference between the VRR simulator and real G-Sync/FreeSync?
    This simulator is a visual explainer, not a hardware test — your browser can't control your monitor's actual variable refresh window. It illustrates why VRR eliminates the stutter/tear pattern you'd get from a fixed refresh rate when frame times fluctuate.
    Is the difference between 60Hz and 144Hz really noticeable?
    Yes, very much so — most visible when scrolling quickly or dragging windows. At 144Hz edges stay sharp; at 60Hz there's clear motion blur. Improvements above 144Hz follow diminishing returns for most people.