Why did I lose when I had taken more of my opponent's pieces?

To goal of the game is to checkmate your opponent, not to have more material. A material advantage is just one of several possible means to this end.
If I'm understanding what you wrote correctly, you ran out of time while your opponent still had time. When that happens, you lose (unless your opponent has insufficient material for a possible mate, in which case you draw).
If this seems unfair because you think that you were winning, consider that your opponent might have been able to obtain a winning position if they had been able to spend more time.
The clock is part of the game. If it's giving you trouble, I'd suggest playing longer games until you're more comfortable with time management. I think that 15|10 rapid games are a good place to begin, since they're short enough to be convenient while long enough to give you some time to think.

If you run out of time you lose. The only exception is if the opponent does not have enough pieces to make a checkmate eg. only a king. It doesn't matter if you have more pieces, will give checkmate next move or whatever. It is not enough to be winning, you must actually win!
Thanks very much for explaining this. I hadn't appreciated that if you run out of time but your opponent still has some time left, you automatically lose. I had thought that account would be taken of the number of pieces you had captured. I'll need to play quicker from now on.
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
That's what a player signs up for when he chooses a specific time control.
Let's use an analogy. I am in a food competition and I have prepared my dish in preparation for the final stage - heating it up in an oven. It takes 5 minutes to fully cook the dish. If I only have 4 minutes left, the food won't be fully cooked. The food will not be safe to eat as it is not fully cooked, regardless of how well I have prepared my dish earlier.
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
Hi!
Nobody likes losing on time, that’s why increment exists and many use it, so you always have at least a second or more added to your clock each time you make a move, giving yourself that time for your next move so if you move fast you can complete the game without losing (or drawing) due to running out of time. If you don’t already play with increment then I recommend it and have peace of mind that the players will have enough time to complete the game before running out of time.
-Jordan
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
Also, that's how your opponent would probably feel when you won on time in a losing position.
You had one game, played within the last 24 hours (at the time of writing), which you won on time in a losing position. You were one full queen down in a game which only had one bishop and two pawns on each side (while White has an extra queen).
In the only other game you won on timeout, you were also in a losing position.

I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
"That's what a player signs up for when he chooses a specific time control.
Let's use an analogy. I am in a food competition and I have prepared my dish in preparation for the final stage - heating it up in an oven. It takes 5 minutes to fully cook the dish. If I only have 4 minutes left, the food won't be fully cooked. The food will not be safe to eat as it is not fully cooked, regardless of how well I have prepared my dish earlier."
Oh okay, I think I get it -- thanks!
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
"Hi!
Nobody likes losing on time, that’s why increment exists and many use it, so you always have at least a second or more added to your clock each time you make a move, giving yourself that time for your next move so if you move fast you can complete the game without losing (or drawing) due to running out of time. If you don’t already play with increment then I recommend it and have peace of mind that the players will have enough time to complete the game before running out of time."
-Jordan
--
Thanks for the info!
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
"Also, that's how your opponent would probably feel when you won on time in a losing position.
You had one game, played within the last 24 hours (at the time of writing), which you won on time in a losing position. You were one full queen down in a game which only had one bishop and two pawns on each side (while White has an extra queen).
In the only other game you won on timeout, you were also in a losing position."
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True, I agree, although I don't see how it's entirely relevant...?
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
"Also, that's how your opponent would probably feel when you won on time in a losing position.
You had one game, played within the last 24 hours (at the time of writing), which you won on time in a losing position. You were one full queen down in a game which only had one bishop and two pawns on each side (while White has an extra queen).
In the only other game you won on timeout, you were also in a losing position."
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True, I agree, although I don't see how it's entirely relevant...?
Because you mentioned "losing from an individual clock even though you had the full upper hand is a little unfair".
Your opponent might have felt the same way too during the two games you won on time, because he was winning.
At the end of the day, in most circumstances almost all of us players have been on both ends of the situation - complaining when losing on time in an otherwise winning position and breathing a sigh of relief when winning on time against our inferior position.
The idea of clocks being there is actually good - it prevents a game from proceeding infinitely. And isn't it fun to watch as either player's time runs out? It gives one the adrenaline which a long game would not usually offer.
I feel like the individual clocks should reset every time the person makes a move, so they don't automatically lose because of a clock and not their mistakes. Perhaps when the game timer stops, and no one has been able to checkmate their opponent yet, then it's a draw. I just feel losing from an individual clock even though you had the full upper hand is a little unfair.
"Also, that's how your opponent would probably feel when you won on time in a losing position.
You had one game, played within the last 24 hours (at the time of writing), which you won on time in a losing position. You were one full queen down in a game which only had one bishop and two pawns on each side (while White has an extra queen).
In the only other game you won on timeout, you were also in a losing position."
---------
True, I agree, although I don't see how it's entirely relevant...?
"Because you mentioned "losing from an individual clock even though you had the full upper hand is a little unfair".
Your opponent might have felt the same way too during the two games you won on time, because he was winning.
At the end of the day, in most circumstances almost all of us players have been on both ends of the situation - complaining when losing on time in an otherwise winning position and breathing a sigh of relief when winning on time against our inferior position.
The idea of clocks being there is actually good - it prevents a game from proceeding infinitely. And isn't it fun to watch as either player's time runs out? It gives one the adrenaline which a long game would not usually offer."
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I feel if there was a game timer that ended and turned the game into a draw when nobody had checkmated someone. Again, yes, he might have felt the same way, and so have I when I have been on the receiving end. I still don't see it's relevance?
But I do agree and get that what you're trying to say, so thanks!

Why don't you play games with increment?
For example, in a 5+5 time control you start the game with 5 minutes on the clock and you gain a bonus of 5 extra seconds with every move you make. So as long as you always make your move within 5 seconds, it's not possible to lose on time... because the bonus time from your previous move gives you the time you need to make this next move.