Walk into any discussion about gaming hardware and three terms get thrown around as if they were the same thing: frame rate, refresh rate and input lag. They are related, but they measure different parts of what happens between you pressing a button and seeing something change on screen. Understanding the difference saves money and stops you from chasing numbers that will not improve your experience.
Frame rate: how often the game draws a new picture
Frame rate, measured in frames per second (FPS), is how many separate images your computer or console produces each second. It is determined by your hardware and the game's settings. A game running at 30 FPS draws a new image roughly every 33 milliseconds; at 60 FPS it draws one every 16.7 milliseconds; at 120 FPS, every 8.3 milliseconds. More frames mean smoother motion and a more current picture of what is happening in the game.
Frame rate depends on the processor, the graphics card, the resolution you choose and the settings you enable. Turning down shadows, draw distance or ray tracing usually raises it. Lowering the resolution does too, because the graphics card has fewer pixels to fill.
Refresh rate: how often the screen can show a new picture
Refresh rate, measured in hertz (Hz), belongs to the display. A 60 Hz monitor updates 60 times per second, a 144 Hz monitor 144 times. If your game produces 140 frames per second but your screen refreshes at 60 Hz, you will only ever see a fraction of those frames. The reverse also matters: a 144 Hz monitor does nothing special if your game only manages 45 FPS.
That is why the two numbers should be matched. For most people, a game that holds a steady frame rate close to the monitor's refresh rate looks better than one that swings wildly between high and low numbers. Variable refresh rate technologies, usually sold under the names G-Sync and FreeSync, let the monitor adjust to whatever the game is producing, which reduces tearing and stutter when the frame rate is not perfectly steady.
Input lag: the delay you actually feel
Input lag, or latency, is the total time from an action, such as clicking a mouse button, to the result appearing on screen. It includes the time the controller or mouse takes to report the input, the time the game takes to process it, the time to render the frame, and the time the display takes to show it. Higher frame rates tend to lower latency because each step happens more often, but frame rate is only one part of the chain.
Several things add latency without changing your FPS counter at all. Some televisions run heavy image processing that adds noticeable delay unless you switch on a game mode. Wireless controllers and mice add a small amount, though modern ones are very good. V-sync can add a frame or more of delay in some games. And online play adds network latency, measured as ping, which no monitor can fix.
Which one should you care about?
It depends on what you play. Slow, cinematic single-player games are perfectly enjoyable at a stable 60 FPS, and a stable 30 FPS on a console is fine for many story-driven titles. Fast competitive shooters and fighting games reward higher frame rates and lower latency, because small timing differences decide outcomes. Rhythm games are particularly sensitive to display lag, and most of them include a calibration screen worth using.
A practical order of priorities looks like this. First, make sure the game runs at a steady frame rate rather than a high but unstable one. Second, check that your display is set to its highest supported refresh rate, because many monitors default to 60 Hz after being plugged in. Third, switch your television to its game mode. Fourth, only then consider buying a faster monitor or a stronger graphics card.
Common mistakes
One frequent mistake is buying a high refresh rate monitor and never changing the setting in the operating system's display options. Another is using a cheap or damaged cable that cannot carry the higher refresh rate at your resolution. A third is assuming a higher number always looks better: beyond a point, usually somewhere above 144 Hz for most players, improvements become hard to notice outside competitive play.
The short version: frame rate is what your hardware produces, refresh rate is what your screen can show, and input lag is the delay between your action and the result. Check all three before spending money, and you will usually find the cheapest fix is a setting rather than a new piece of hardware.