The clock is wrong, constantly

I play a lot of bullet, and I noticed that even in the best possible conditions, if I don't premove I lose about 1 second every move. This does not seem to happen to any streamer using this site, why is it happening to me? I played a bit with reflex testing apps, and usually I have a pretty good time of response (0.2-0.25 seconds), so it's not just that I am too slow.

Tipical situation:

Let's say I already know what my next move is going to be, I am hovering with the piece on its next square and I am just waiting for my opponent to move, I release the piece and I should have lost just 0.25-0.3 seconds, right? (I take a bit more just for extra safety). Still, the clock shows that I lost a full second. Then it's my opponents turn. He takes at least x2 what I took to move: his time goes down by half a second.

I have noticed this with different computers, different connections, even from different countries. Is it a problem with the location of the servers? I am not really sure how the site works in the background.

If not altready done, couldn't the time be calculated locally in the browser instead that by the moves arriving to the server? The way it is right now, when playing fast time controls feels like your connection is more important than your skill.

There are a number of things that can be done to combat lag.

https://support.chess.com/article/213-how-do-i-fix-my-disconnect-lag-issues

As to how the times are calulated, the client does send the time taken and the the server will calculate the lag and compensate for some of it. However, there is a max amount of lag that is allowed and anything over that counts against the player's clock.

https://support.chess.com/article/423-why-did-the-clock-times-suddenly-change-the-clocks-seem-broken

Hi Martin, thanks for your answer.

The way chess.com calculate the time seems pretty resonable, but it still feel off to me during the game, great part of the times I feel like I am moving at the same speed of my opponent and, on a 1 minute game, I end up with no time while he has 25+ seconds.

I am not sure this is a lag issue either, I generally have all 4 bars and when I do the /ping it showes up as:

95ms (Type: ssl-websocket, Network: live)

Ok, sometimes I lose connection (I am on wi-fi), but it's pretty rare. Could it be that I have many micro-disconnections and the connection bar does not pick it up, but the clock does?

Yes, that is very possible. But it could also because by resends of the data packets. If a number of your moves don't make it to the server on the first try or if you don't receive your opponent's move from the server due to lag or lost packets, that can add up. It would be especially noticable in bullet.

It happens to me that I pre-move, one second passes, and the clock goes down for me 3 seconds. The result is that my clock goes down all the way and my opponent has 30 seconds when i have been premoving. How is this possible? It also happens to me constantly.

Sounds like a poor connection to the server.