What is being counted
A refresh rate is the number of times per second a display can redraw its image, measured in hertz (Hz). A 60 Hz screen can update 60 times a second; a 120 Hz screen, 120 times. Each update shows whatever frame the source is currently sending. It is a property of the screen, not of the content, and the two are often confused.
It helps to separate three related numbers:
- Refresh rate is how often the screen can update.
- Frame rate is how often the source, such as a game, video file or computer, produces a new image. It is measured in frames per second.
- Response time is how quickly an individual pixel changes color, which is a separate matter that affects blur.
A high refresh rate shows new frames sooner only if frames arrive that fast. A 144 Hz monitor showing a 30 frames-per-second video still shows 30 distinct images per second.
Frame time
Dividing one second by the refresh rate gives how long each refresh lasts. These figures are rounded:
| Refresh rate | Time per refresh |
|---|---|
| 60 Hz | about 16.7 ms |
| 120 Hz | about 8.3 ms |
| 144 Hz | about 6.9 ms |
| 240 Hz | about 4.2 ms |
The step from 60 to 120 Hz saves about 8.3 ms per refresh, while the step from 120 to 240 Hz saves about 4.2 ms. The gain in time gets smaller each time the rate doubles, which is one reason the improvement from 60 to 120 Hz is often felt more than 120 to 240 Hz, though people differ.
How refresh rate relates to smooth motion
Smoothness of motion comes from several factors. A higher refresh rate helps in two main ways.
More frequent updates. Moving objects advance in smaller steps between refreshes, so motion looks less jumpy, provided the source supplies matching frames. Scrolling text, moving a mouse cursor and fast camera pans are common places where people notice the difference.
Less perceived blur. On many modern screens each image is held on screen until the next one replaces it, a “sample and hold” behavior. As your eye tracks a moving object, a held image smears across the retina, which is perceived as motion blur. Shorter hold times reduce this, and a higher refresh rate shortens the hold. The effect is part of why the motion blur you see is not entirely about pixel speed. Some displays also use backlight strobing to cut the hold time at the cost of brightness and, for some people, visible flicker.
Smoother motion also depends on the pixels keeping up. If pixel transitions are slower than the refresh interval, the response time can leave trails even at a high rate.
Matching content to the rate
A fixed refresh rate creates timing problems when the source’s frame rate does not divide evenly into it.
- Film at 24 frames per second on a 60 Hz screen cannot be spaced evenly: 60 ÷ 24 = 2.5, so some frames are held for two refreshes and others for three, producing a slight judder in pans. A 120 Hz screen divides evenly (120 ÷ 24 = 5), which is one reason it suits film, and many screens also have a 24 Hz-compatible mode.
- Games with variable frame rates may produce a new frame partway through a refresh. Without adjustment, the screen can show parts of two frames at once, which is screen tearing, or the system waits for the next refresh, which adds delay. Variable refresh technology, usually called adaptive sync, lets the screen adjust its refresh timing to match the source, reducing both problems within the screen’s supported range.
Settings matter, too. Some systems default a new monitor to 60 Hz regardless of its capability, and the higher rate must be selected in the graphics settings. A cable or port that cannot carry the combination of resolution and refresh rate may force a lower one, a common limitation among video connectors.
When higher rates matter
Higher refresh rates tend to be most noticeable in:
- Fast action games and competitive play, where more frequent updates and lower delay can help, as in discussions of esports displays and gaming monitors. The benefit depends on the system actually producing high frame rates.
- Scrolling and pointer movement, where the improvement is visible even in everyday use, such as smartphone screens with higher rates.
- Virtual reality, where a high refresh rate helps comfort and motion clarity.
They matter less for:
- Reading, spreadsheets and static documents.
- Standard video at 24, 25 or 30 frames per second, unless the screen’s rate fits it better.
- Anyone whose hardware cannot produce frames beyond a modest rate.
Perception varies a great deal. Some people see a clear difference between 60 and 120 Hz immediately; others hardly notice. Differences between very high rates are subtler still.
Costs and trade-offs
High refresh rates need more of the system:
- Processing. The graphics source must render more frames per second.
- Bandwidth. The connection carries more data per second, which may limit resolution, color depth or other features at the highest rates.
- Power. Panels refreshing faster can draw more power, and portable devices often lower the rate when the screen is static to save battery. That is part of why adaptive-rate screens are used.
- Price. Faster panels tend to cost more, though costs shift over time.
Reading refresh rate on a spec sheet
The refresh rate is one of the easier figures to trust, since it is clearly defined and simple to check in your settings. Still, check these points:
- Is the listed rate available at the resolution you plan to use, or only at a lower one?
- Does the connection you will use support it?
- Does the rate come from an “overclocked” or special mode with caveats?
- Is the panel’s pixel response fast enough to make use of it?
A high refresh rate is a capability. Its value depends on content, hardware and your own sensitivity to motion.