# Refresh rate, response time and motion clarity > A monitor shows a succession of still images. How many per second, and how fast its pixels move from one to the next, determines whether motion looks fluid and sharp or jerky and smeared. Source: https://monitorselector.com/en/refresh-rate-response-time/ (Monitor Selector, 2026-11-14) ## In short - The refresh rate (Hz) is the number of images shown per second. Frame time = 1000 ÷ Hz: 16.7 ms at 60 Hz, 6.9 ms at 144 Hz. - On a screen that holds each image, motion blur is proportional to frame time: doubling the rate halves the blur. - For desk work, 100 to 120 Hz makes scrolling and pointer movement visibly smoother. For games, 144 Hz is the base. - A high rate is only useful if the computer produces that many images, and if the response time of the panel keeps up. ## Frames and frame time The refresh rate, in hertz, is the number of times per second the monitor redraws its image. Its inverse is the frame time, the duration each image stays on screen: frame time (ms) = 1000 ÷ refresh rate (Hz) ***Fig. 1.** Images shown during one tenth of a second. Doubling the rate halves the time each image stays on screen, and the blur the eye perceives when following motion.* From 60 to 120 Hz the frame time falls from 16.7 to 8.3 ms, a gain of 8.3 ms. From 120 to 240 Hz it falls to 4.2 ms, a gain of 4.2 ms only. Each doubling brings half the benefit of the previous one: the step from 60 to 120 Hz is obvious to everyone, the step from 240 to 480 Hz is discernible mainly by trained players. ## Why motion looks blurred: sample-and-hold A flat panel displays each image and holds it, unchanged, until the next one. When you follow a moving object with your eyes, they glide continuously while the image stays still for the whole frame time; the object is therefore smeared across your retina over the distance your gaze has covered meanwhile. blur (pixels) = speed (pixels per second) × persistence (seconds) An object crossing a 1440p screen in about 2.7 seconds moves at 960 pixels per second. At 60 Hz it is blurred over 16 pixels, at 120 Hz over 8, at 240 Hz over 4. This blur exists even with pixels that would switch instantly: it comes from the eye, not from the panel. It is the main reason why a high refresh rate looks sharper in motion, and it explains why text remains readable while scrolling on a 120 Hz screen and turns into grey bars at 60 Hz. Some monitors reduce persistence differently, by flashing the backlight briefly for each image (backlight strobing) or inserting black frames. Blur falls sharply, at the cost of brightness and sometimes visible flicker; the technique is aimed at competitive play. ## Response time: the panel’s own delay The response time is the duration a pixel takes to pass from one shade to another, generally measured from grey to grey (GtG). If it exceeds the frame time, the pixel has not finished its transition when the next image arrives, and a ghost trail follows moving objects. To be invisible, the response should stay clearly under the frame time: under 8 ms at 120 Hz, under 4 ms at 240 Hz. Orders of magnitude by technology: - **OLED:** about 0.1 ms, negligible at any refresh rate; - **fast IPS:** 2 to 5 ms in real measurements; - **VA:** 4 to 8 ms on average, but 15 ms and more on some transitions between dark shades. The “1 ms” printed on boxes is a best case obtained with the most aggressive **overdrive** setting. Overdrive accelerates transitions by briefly over-driving the pixel; pushed too far it overshoots the target and draws a bright or coloured halo behind objects. The middle setting is almost always the right one. Independent measurements are the only reliable source on this point. MPRT, another figure found on specification sheets, measures the persistence described in the previous section, not the speed of the pixels. A “1 ms MPRT” is obtained with backlight strobing. ## Variable refresh rate A game does not produce its images at a regular pace: 97 per second in one scene, 71 in the next. A screen with a fixed rhythm then has two bad options, showing part of one image and part of the next (tearing), or waiting for the next cycle (stutter and added delay). Variable refresh rate (VRR) removes the dilemma: the monitor waits for each image and displays it when it arrives. The technique exists under the names G-Sync (Nvidia), FreeSync (AMD) and Adaptive-Sync (the VESA standard); the three are largely interoperable today. It works within a range, for example 48 to 144 Hz; below the range, monitors with low framerate compensation repeat each image to stay within it. For games, VRR matters as much as the maximum rate. ## What rate for what use ### Office work and code Nothing requires more than 60 Hz to display a document. But scrolling a page, moving a window or simply following the pointer are movements, and they are twice as sharp at 120 Hz. Those who have worked on a 100 or 120 Hz screen rarely go back. Since such panels now cost barely more, the selector suggests 100 Hz as a sensible target for work whenever the budget is not tight. ### Games 144 Hz is the base, 165 to 240 Hz the comfortable range, and higher rates concern competitive shooters. The rate is useful only if the graphics card follows: a screen at 240 Hz fed 80 images per second shows 80. Hence the classic pairing of 1440p with 144 to 240 Hz, which mid-range cards can drive, while 4K at 144 Hz requires the top of the range (see [resolution and scaling](https://monitorselector.com/en/resolution-and-scaling/)). ### Video and creative work Films are shot at 24 images per second, broadcast video at 25, 30, 50 or 60. A rate of 120 Hz has the merit of being a multiple of 24, 30 and 60: each image is repeated a whole number of times and motion is free of judder. For editing, colour precision matters far more than rate. ## Input lag Input lag is the delay between the arrival of the signal and the display of the image: the processing time of the monitor’s electronics, to which half a frame time is added on average. Good monitors add less than 5 ms. A high refresh rate reduces the total mechanically, which is the second reason competitive players seek it. For work the question does not arise, with one exception: televisions used as monitors, whose image processing can add 50 ms or more unless a “game” or “PC” mode is activated. A high rate also raises the data to transport. 1440p at 240 Hz or 4K at 144 Hz exceed older ports; the chapter on [connections](https://monitorselector.com/en/hdmi-displayport-usb-c/) tells which link carries what. ## Frequently asked questions ### Is 60 Hz enough for office work? Yes, to display documents. But 100 or 120 Hz makes scrolling, window movement and the pointer visibly smoother and sharper, for a small price difference today. If you spend your days in long documents or code, it is a comfort worth having. ### Can the eye see more than 60 Hz? Yes. The eye does not see in frames: it perceives the blur and the stepping that a succession of still images produces when something moves. That blur halves between 60 and 120 Hz and halves again at 240 Hz, and both steps are visible in direct comparison. ### What matters more for gaming, refresh rate or response time? Both are needed together: the refresh rate sets how many images you see, the response time sets whether the pixels finish changing before the next one. A 240 Hz panel with slow pixels smears; choose according to measured response times, not the “1 ms” of the box.