Losing

Could someone please explain to me; How does that work? More than once now, I was winning a game, having many more of the other person's pieces, including the good ones like the queen and the bishop, and the other person having just a few of mine. The other person didn't put me in check at all either, yet at the end of the game, it says that the other person won. What could have gone wrong?

Greetings Kamila Godzinska!  I believe that you may have run out of time on your clock.  Usually chess games are played with Chess Clocks!  If this helps you with this problem.  Please let me know!  Vh1

You probably lost on time. Is this live chess or online? Either way there is a time limit that you must be aware of.

Edit: I see that this is posted in the live chess forum so I'm assuming it is live chess. In this case the time controls are in the format x|y, where x is the number of minutes you start the game with, and y is the number of seconds added to your clock each move you make. If you run out of time you will lose. 5|0 would give you 5 minutes to make all of your moves, and 5 minutes for your opponent to make all of his moves. 5|2 is the same but with 2 seconds added to your clock every move.

Thanks very much, I found both responses helpful!