Hi guys! As I mentioned on previous contest I'm working on tool that predicts rating changes. I'm happy to present it now!
A huge amount of your nerve cells die every time when you wait for a rating update on Codeforces. Stop this! From now you could use this service, it calculates approximate rating changes for every contestant.
The most interested thing for you is chrome extension. It partly modifies the contest standings page and shows approximate rating changes for every contestant. You could find it here.
Also you could find more detailed information (seed, rank, expected delta, etc.) here.
A project still in beta, so predictions are not very accurate. Average mistake around 5 points, but for the contestants at the back of standings it could be greater up to a few hundreds.
I'd like to thank Rubanenko and all other members of NBHEXT developers team for your shared sources and MikeMirzayanov for the great Codeforces platforms with shared API & ratings formulas.
P.S. I would be happy if somebody find bugs in my rating calculation.