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What is refresh rate (60 Hz vs 120 Hz vs 144 Hz)?

In one sentence: How many times a second a screen redraws its picture, such as 60, 120 or 144 times (Hz); more redraws look smoother if the game keeps up.

A little more

A screen doesn't show moving pictures continuously. It redraws the whole picture on a steady beat, and the refresh rate is how many times a second that happens, measured in hertz (Hz). At 60 Hz there are 16.7 milliseconds between pictures, at 120 Hz 8.3 ms, at 144 Hz 6.9 ms and at 240 Hz 4.2 ms.

Refresh rate is the screen's side; frame rate is the game's or video's side, how many new pictures it makes each second. A 144 Hz screen showing a 60 fps game mostly shows each picture more than once, so you need both to be high to get the smoothness. Going from 60 to 120 Hz is easy to see, mostly as sharper, smoother movement; each step after that saves less, because the gaps are already short.

See it in action

  1. BonusWhy does a game judder when it can't keep up?A screen is a flip book with a thumb that turns the page on a steady beat, and the game is an artist drawing the pages.9 min · interactive
  2. BonusHow does a game controller talk to a console?Your controller fires tiny paper darts at the console hundreds of times a second, each one a snapshot of every button and stick.8 min · interactive
  3. BonusWhy does the TV say "No signal"?Before any picture appears, a console and a TV shake hands: the TV says hello, hands over a menu card of every picture it can show, the console picks the best one on both lists, and for films they swap a secret password.9 min · interactive

Do it for real

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Related words

  • Frame rate How many still pictures a video shows each second (fps). More frames look smoother but take more space.
  • VRR (variable refresh rate) When the screen waits for each new picture from the game and redraws right then, instead of on a fixed beat, so there is no tearing or stutter.
  • Input lag The delay between pressing a button and seeing the result on screen, made of the controller, the connection, the game's frames and the screen added together.
  • Screen tearing A line across the picture where the top shows one frame and the bottom the next, because the screen swapped pictures halfway through drawing.
  • HDR (high dynamic range) A way of describing pictures with much brighter highlights, deeper shadows and more colours than ordinary video; the screen then squeezes it into what it can actually show.
  • EDID The menu card a TV or monitor hands over when you plug it in: its name, every picture mode it can show and whether it can do HDR, so the device can pick one.

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