Refresh Rate Test

What this refresh rate test measures

The refresh rate is the number of times per second your screen shows a new picture. It is given in hertz (Hz): 60 Hz means 60 pictures per second, 144 Hz means 144. A higher rate makes scrolling, the mouse pointer and games look smoother.

A screen sold as “144 Hz” does not always run at 144 Hz. The system may be set to 60, the cable may not carry more, or a power saving mode may have lowered the rate. This test shows the rate that is really in use, as your browser sees it:

• Refresh rate. Measured over five seconds, with one decimal.
• Closest standard rate. The rate screens are sold at that matches your measurement: 60, 75, 120, 144, 165, 240 Hz and others.
• Skipped frames. Pictures that should have been drawn and were not.
• A plain explanation of what the result means, including when the browser itself limits the value.

Nothing is installed, no permission is asked and nothing leaves your browser.

How to use it

1. Open the page and wait five seconds. The measurement starts by itself. Keep the window in front and do not scroll while the bar fills.
2. Read the result under “Your results”: the rate, the closest standard rate, the skipped frames and the explanation.
3. Look at the three lanes under “See the difference”. The same block moves at your screen’s rate, at half of it and at a third of it.
4. Change something, then press “Measure again”: another refresh rate in your system settings, another cable, the charger plugged in, the window moved to a second screen.
5. Save the result to compare it later or to send its link to someone.

How to read your results

Refresh rate

The page counts the frames your browser draws and times them. A browser draws one frame each time the screen refreshes, so the two normally match. The value has one decimal because real screens are rarely on a round number: 59.9, 143.9 or 164.8 Hz are normal readings for screens sold as 60, 144 and 165 Hz.

Closest standard rate

Screens are built for fixed rates. When your measurement is within 2% of one of them, the test names it. “No match” means the rate moved during the five seconds. That happens when the device is busy, when a power saving mode switches on, or with a variable refresh rate. Measure again with the window in front and nothing else running.

Skipped frames

A frame is skipped when the browser was not ready in time and the screen showed the previous picture again. One isolated skipped frame is normal. Many skipped frames mean that the device was busy: other tabs, a video call, an update running in the background, or a laptop saving its battery. The chart shows them as taller bars.

Skipped frames describe this page during these five seconds. They do not show a fault in the screen.

The three lanes

The first lane is redrawn on every frame. The second is redrawn every second frame, as a screen with half the rate would show it, and the third every third frame. On a 144 Hz screen you see 144, 72 and 48 pictures per second side by side. If the three lanes look the same to you, raise the speed: the gaps between two positions of the block become wider and easier to see.

Why it shows 60 Hz on a 120 or 144 Hz screen

This is the most common surprise. Check these causes in order.

The system is set to 60 Hz

A new screen, a new cable or a driver update often puts the rate back to 60 Hz. The next section shows where to change it.

The cable or the port does not carry more

The rate a cable can carry depends on its version and on the resolution.

Many screens reach their highest rate only through DisplayPort, or through one particular HDMI port: the manual says which. USB-C docks and adapters are often limited to 60 Hz.

The browser limits pages

Safari on a Mac, and every browser on iPhone and iPad, usually limits web pages to 60 frames per second, even on a 120 Hz ProMotion screen. The test says so when it detects this case. Your screen then runs faster than the measurement shows, and no web page can prove it. On a Mac, measure again with Chrome, Edge or Firefox.

A power saving mode is on

Battery savers lower the rate to save energy. Low Power Mode on an iPhone, the battery saver of a laptop or an Android phone, and the energy saver of some browsers can bring pages down to 60 or even 30 frames per second. Plug in the charger or turn the mode off, then measure again.

The window is on another screen

With two screens, the browser follows the screen that shows its window. Move the window entirely onto the screen you want to test and press “Measure again”. When one picture is duplicated on two screens, both usually run at the rate of the slower one.

How to change the refresh rate

• Windows 11. Settings, System, Display, Advanced display, then “Choose a refresh rate”.
• Windows 10. Settings, System, Display, Advanced display settings, then “Refresh rate”.
• Mac. System Settings, Displays, then “Refresh rate”. On a MacBook Pro with ProMotion, choose ProMotion.
• Android. Settings, Display, then “Smooth display”, “Motion smoothness” or “Refresh rate”: the name depends on the brand.
• iPhone and iPad. Models with ProMotion change their rate by themselves. Settings, Accessibility, Motion, “Limit Frame Rate” keeps them at 60 Hz when it is switched on.

If the rate you expect is not offered, the cable, the port or the graphics driver is the limit.

Troubleshooting

The value changes from one measurement to the next

A difference of a few tenths is normal. A larger one means that something else was using the device. Close other tabs and programs, wait for the page to finish loading and measure again. Phones and some laptops also lower their rate when nothing moves on the screen.

Many skipped frames

Close video calls, games and heavy tabs. On a laptop, plug in the charger. Browser extensions that change every page can also slow the drawing: try a private window, where extensions are usually off.

The rate is right in the system settings but the test shows less

Check that the window is on the right screen, that no power saving mode is on, and that the browser is not one that limits pages (see above). On a remote desktop session, the rate is the one of the remote connection, not of your screen.

The rate is about 30 Hz

A power saving mode is almost always the cause. A very busy device can also fall to half its rate: the skipped frames then show it.

Frequently asked questions

Is anything recorded or sent to TestrHub?

No. The measurement runs in your browser and nothing leaves it. Saved results stay in your browser, and a result is only shared if you copy its link.

What is the difference between hertz and frames per second?

Hertz describe the screen: how often it can show a new picture. Frames per second describe the program: how many pictures it produces. A game that produces 200 frames per second on a 60 Hz screen still shows 60. This test measures the frames your browser draws, which follow the screen.

Why 59.9 Hz and not 60?

Many screens run at 59.94 Hz, a value inherited from television, and others are a few hundredths above or below their nominal rate. The test shows what it measures, and “Closest standard rate” gives the round number.

Can the eye see more than 60 Hz?

Yes. Most people notice the difference between 60 and 120 Hz when they scroll or move a window. The gain from 144 to 240 Hz is smaller, and matters mostly in fast games. The three lanes let you judge for yourself.

Does this test measure response time or input lag?

No. Response time is how fast a pixel changes colour, and input lag is the delay between an action and its picture. Both need a camera or a measuring device in front of the screen: a web page cannot see what the screen really shows.

Which test should I run next?

The screen test checks the same screen for uniformity, backlight bleed and banding, and the dead pixel test looks for faulty pixels.