Why is are my 5 minute and 10 minute ratings so different?

I'm pretty stable (stagnant) around 700 on 5-minute games, and yet over 1000 in the 10-minute games. I often feel the opponents aren't as good in the 10-minute games, yet our ratings are higher.

I guess the ratings are determined by a win/loss ratio or whatever, but was wondering if anyone else had the same experience or possible explanation?

Maybe not then.

So the longer the game, the higher everyone's rating is? 

Not always true. My bullet rating > blitz rating > rapid rating on this site.

But in general, it depends on your game play. If you use your time to ensure no pieces are blundered. longer controls suit your game play better (hence, a higher 10-minute rating than 5-minute rating).

Emm the rating scales are just not meant to be calibrated to each other. I think the blitz is lower for pretty much everyone below a certain point (like if your rapid is below idk 2000, your blitz is almost surely lower than rapid).

My no time elo is around 1450. My 5 minute is around 300. Big difference...

It's because 10 minute is actually blitz but Chess.c don't understand that. They're the only people in the World who don't understand it. So you may be playing people at 10 minutes who are used to slower rapid speed. Too fast for them.

I play worse the less time I have. When I played 15 - 10 rapid my elo was in the 1000 to 1100 range, but when I switched to playing 10 - 0 games I dropped to 700 to 800. My blitz is in the 500's, and I rarely play bullet at all because there is no time to think. Some people are better at playing fast but I am not one of them.

Probably you didn't practise much at 5 mins OR you're a beginner and need more time for that reason.

Had to google that for USCF and FIDE. This is new to me.

10 minutes was always a kind of slow blitz speed, with more in common with 5 minutes than with 15 minutes. They changed it due to pressure from some people but all the proper chesss bodies accepted 10 mins as blitz last time I looked. 10 mins + increment is rapid.

I think more beginners play rapid. A lot of people who are just starting out feel like they need time to think. Most creators and coaches also advise against blitz for beginners. Therefore, the weakest blitz players are way stronger than the weakest rapid players. The result is that blitz is lower than rapid on average at most ratings.

The active player pool is weaker at 10 minutes.

10|0 is considered blitz? I agree with this classification versus calling it rapid.

Yes. You should find that all the chess bodies call 10 mins plus increment "rapid" but 10 mins no increment has always been a blitz rate of play.