I was discussing with my colleague at work about how I found input lag annoying and he made some comment about how I probably can’t notice ~10-100ms of input lag. Well, eager to prove my point I made a little game to test this assumption.

This game concerns a very exciting square. When you click the square, it will toggle between black and white. The aim of the game is to decide whether there is a lag between the click and the colour switch. Secretly, the game has decided whether or not it will produce a small (Xms) delay. You have to decide whether you think you see it or not and click either “Lag” or “No lag”. Once you clicked it, the game records whether you were right and then resets itself so you can try again. After a number of attempts, the game will tell you whether you managed to convince it that you can tell the difference.

Click to toggle
No lag
So... can you tell?

Turns out, I can just about recognise Xms lag. I was expecting to be able to recognise lower numbers, but the game proved me wrong. Can you spot the lag?

Apologies to anybody viewing this on mobile, it’s not as easy to judge the timing with a touchscreen. You’ll have to wait until you’re sat at a computer with a mouse in your hand.