This refresh rate test measures how many frames per second your display actually renders, right now, in your browser. Apple’s ProMotion screens run up to 120Hz, standard iPhones and most Macs run at 60Hz, and some external monitors go far higher — but the number you’re promised on the box isn’t always the number you get, especially in Low Power Mode or when a browser throttles animation.
The tool counts real animation frames over a rolling window and reports a live Hz reading, then classifies it: 120Hz ProMotion, 60Hz standard, or the exact rate of your external monitor. Because browsers cap animation to the display’s refresh rate, this reflects the true rate your screen is driving at that moment.
How to use it
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1Start measuring
Tap “Measure refresh rate”. The live reading appears within a second and keeps updating as it samples more frames.
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2Let it settle
Watch for two to three seconds until the number stabilises. The moving bar gives you a visual feel for the smoothness at your rate.
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3Read the result
Around 120Hz means ProMotion is active. Around 60Hz is standard. Anything else is your monitor’s native rate. On iPhone, disable Low Power Mode for the true figure.
Frequently asked questions
How do I know if ProMotion is working on my iPhone or iPad?
Start the test and watch the live reading. If it settles near 120Hz, ProMotion is active. If it reads about 60Hz on a device that supports 120Hz (iPhone Pro models, iPad Pro), check that Low Power Mode is off and that “Limit Frame Rate” isn’t enabled under Settings → Accessibility → Motion.
Why does my 120Hz screen show 60Hz?
The most common causes are Low Power Mode, the Accessibility “Limit Frame Rate” setting, or the display dropping to a lower rate to save power when little is moving on screen. Keep the moving bar animating and the rate should climb to its maximum.
Is this refresh rate test accurate?
It measures the frames your browser is actually able to paint, which is capped by the display’s refresh rate. For typical use it’s an accurate reflection of the rate your screen is driving. Very high-rate gaming monitors may read slightly under their peak due to browser overhead.
Does it work on external monitors and Windows PCs?
Yes. Although this site focuses on Apple devices, the test is display-agnostic and measures any screen the browser is running on, including 144Hz and 240Hz monitors on Windows.