What is ping, and why do online games lag?

Ping is a delay, not a speed

When you press a button in an online game, your computer sends a message to a faraway computer called the server. The server decides what really happened and sends the answer back. Ping is how long that round trip takes, in milliseconds (ms). A ping of 40 ms means 0.04 seconds from "you pressed fire" to "the server's reply is back on your screen".

Part of that time is just physics: signals in cables travel at roughly two-thirds the speed of light, so a server 5,000 km away costs you tens of milliseconds even on a perfect line. The rest comes from routers along the way and your own home network. That is why a nearby server usually means a lower ping.

Latency, bandwidth and packet loss are different things

A fast "100 Mbps" plan is about bandwidth. Games send small, frequent messages, so they need very little of it; downloading a game needs lots. That is why an expensive plan will not fix a high ping. Packet loss is the nasty one: even 1 to 2 percent lost packets can make a game feel jumpy, because the game has to guess what it missed.

One more word you will see in menus is jitter: how much your ping bounces around. A steady 60 ms is easier to play on than a ping that swings between 20 and 150, because the game cannot settle into a rhythm and has to guess more often.

See it for yourself

Drag the player left and right in the top lane. The bottom lane shows where the server thinks you are. Raise the ping and the server's version trails behind. Raise the packet loss and it freezes, then snaps forward when an update finally gets through. That snap is rubber-banding.

Client, server and tick rate

Your computer is the client. The server is the referee: it keeps the one true copy of the match and decides who hit whom. The server does not update continuously. It runs in steps called ticks, and the tick rate is how many it does per second. A server at 64 ticks per second updates the world about every 16 ms; at 128 ticks, about every 8 ms. Many popular shooters sit somewhere in that range, and some games run slower, which is one reason the same ping can feel different between games.

Why other players do not stutter: interpolation

Updates arrive in separate snapshots, not as smooth video. If the game drew other players exactly where each snapshot said, they would teleport between positions. Instead your game interpolates: it draws other players slightly in the past and slides them smoothly between the last two snapshots. The price is that everything you see about other players is a little old, by roughly your ping plus the interpolation delay.

Why you get shot behind a corner

This is the famous peeker's advantage. Imagine you stand still behind a wall and an enemy steps out to look. On their screen they see you right away and shoot. That shot travels to the server, which has to check it against where you were. Meanwhile, on your screen, the enemy has not appeared yet, because news of their movement is still travelling to you. By the time you see them, the server may have already confirmed the hit, so you feel killed "after" you reached cover.

Nobody is cheating here. Both players are looking at slightly different, slightly old versions of the match. Many games try to make shooting feel fair by having the server rewind a little to check what the shooter could see, which is why the person moving usually has the small edge.

What you can do about it

• Use a wired connection if you can; Wi-Fi adds delay and random packet loss.
• Pick the nearest server region in the game's settings.
• Pause big downloads and streaming on the same network while you play.
• As a rough guide, under about 50 ms feels fine for most games, and many fast shooters feel noticeably worse above roughly 100 ms. These are rules of thumb, not hard limits.

Remember the difference from the table: a faster plan helps bandwidth, but ping and packet loss depend on distance, your local network and the route to the server.