How does Chess.com's rating system work?

Can anyone explain how Chess.com's ratings work? I won a game and my gain in rating was not equal to my opponent's loss of rating. Please explain, 'cos I heard that my gain must equal his/her loss.

https://support.chess.com/customer/en/portal/articles/1444777-how-do-ratings-work-

Rating gained by one player usually isn't the same as the rating lost by the other. I can be but most often isn't.

The link Martin_Stahl posted should go into more detail, but basically chess.com uses a slightly different rating system called the Glicko system. 

Glicko ratings include a measure of the uncertainty of each player's rating in its calculations. 

Simply put, if chess.com is uncertain that your rating is accurate, then your rating will have larger changes (to get you to your correct rating faster).  On the other hand, if it is uncertain that your opponent's rating is accurate, then your rating will have smaller changes (so that you are not unduly punished or rewarded for playing someone whose rating is vastly different than their skill).  Put together, this often means that ratings changes between opponents is asymmetric.

Does anyone know how many moves have to be played in a 'DAILY' game before the ratings actually kick in. So if there are 4 moves made by white but only three moves made by black and the game then times-out will the ratings adjustment kick in or not. No guessing answers please. There IS an exact answer to this question but trying to find out what it is on this site is like trying to squeeze blood out of a stone. They are so secretive about it for some reason.

Yes, they keep the secret answers on the Help pages.

Nobody would ever think to look there!

https://support.chess.com/article/599-the-game-ended-and-my-rating-didnt-change-at-all-why

Thank you for your reply, I don't know why you set the print to be so large as my eyesight is okay thank you. I can read normal size print.

If you made the size of the print large because you are one of these people that think whoever shouts the loudest must be right then I feel sorry for you.

I think you are wrong on both counts anyway because I've read somewhere else on here that resignations always incur a ratings loss even if made after just one or two moves in a game.

And you are just as vague as the site when it comes to how many moves, you say 4 but what if I am black and my opponent makes 4 moves and I only make 3 moves, will the ratings kick in then? I'm not looking for vague guesswork answers I am trying to find out the exact and correct way the system works thank you.

John helpfully posted a link to the source above the cut and paste so that you are able to check the information for yourself. The information is from Chess.com. It is not his opinion and probably not his choice of text size - cut and paste.

Apology accepted (if that's what it was?).

And of course I did follow the link that your friend provided and the site is vague about the ratings system, as I pointed out already.

I don't suppose you know the answer to my original question do you GrubbMark.

If I am black and only make three moves in a game (even if my opponent who is of course white has made 4 moves), and then the game times out, will the ratings system come into effect? Many thanks if you are able to give me a definitive (correct) answer.

It wasn't an apology. 

The answer seems pretty clear to me.   

I think there is no point in explaining any further. 

The only way to know for certain is to go and try it yourself.

6 ply in a daily game ending in timeout: no rating change

7 ply in a daily game ending in timeout: rating change

So the answer is yes.

(Took me a few minutes of randomly looking through someone's history.)

https://www.chess.com/games/archive/discusshothammertoss?gameTypesdaily%5B%5D=daily&gameOwner=other_game&gameType=daily&opponent=ChessLife65&rated=rated&timeSort=desc

Thank you very much Llama, that's the definitive answer I was looking for. No guesswork from you.

Years ago the site told people this information as soon as they joined the site but these days that information seems to be be a lot harder to find out. I can't think why.

Notmytwin. No need for me to go try it for myself now. Llama came up with the information I was looking for. No spam from him. He's the man. He's the dude. He knows what he's talking about. He was able to explain in detail the answer to my original question. He ought to get a job working for chess.com.

They have updated their answers in Help recently. It does seem like the current answer is  somewhat ambiguous.

The Wayback Machine shows that the old answer was more precise:

Thanks @star_seed

Although the attacking @notmtwain stuff makes me a bit uncomfortable. He's been around a long time and helped a lot of people.

As for chess.com and info, maybe they think most people wont care? I don't know. I remember once I accidentally started a live game and after 1 move I resigned, thinking I wouldn't lose points, but I did

I know what you are saying about starting a a live game by accident and then losing points. It happened to me. I think the problem was that chess.com started you in a game as soon as you clicked the 'START NEW GAME'  button. The site never gave you a chance to go to the live place and then decide if you wanted to play or who you wanted to play. As soon as you pressed the NEW GAME button the site started you off in a game (a timed game) even if you didn't know about it happening! You might have gone into the kitchen to make a cup of tea or gone to the toilet and then you'd come back to your computer to discover that you'd lost a game! It happened to me a few times. Badly thought out. Nowadays I think they've made it better insofar as when you press the NEW GAME button now it takes you to a place where you can choose if you want live or daily, a custom game, chose your parameters (5 days 7 days etc...)

I don't mean to sound impatient regarding the answers from Notwain. It's nothing personal I just hate it when people pretend they know what they are talking about and don't really have a clue. I hate it when people try to bull***t. As far as I'm concerned if you don't know the answer you shouldn't pretend that you do know the answer, you should just say sorry I don't know. Maybe I suffer from a form of OCD but I like things to be right. No ifs or buts, no grey answers... pretending you know... when you don't. It doesn't help me, Whether he's helped other people or not, it doesn't help me if he comes out with a load of soap bubbles. He might as well just say 'I don't know the answer'. I'd respect his honesty a lot more than him pretending to be the man. Don't you find it infuriating when people try to snow you Eric? Haven't you ever had to deal with a big corporation or a government departtment and all they try to do is fob you off with fog, snow, smoke and mirrors, false information and downright rhubarb? Doesn't it make you mad when people take you to be a fool that they can bull***T you? It infuriates me Eric.