What is the engine used in the self-analysis after a game? Is it or something similar available?

i really enjoy the engine's ability to quantify the strength of various choices and graph it. It was recommended that i go through games making sure my numbers do not swing wildly, a mark of uneven play. I don't know what I would call that option to search for it. Where can I buy it or something similar? Something that would allow me to cut and paste or enter old games for study.  

It's called a PGN, and you can get it for any game easily on this site...

PGN stands for portable game notation has nothing to do with what OP is asking about.

As far as I'm aware it's Stockfish, since when you pull up game analysis online it's running a stockfish javascript file. You can analyze games on chess.com even if you did not play them here by going to https://www.chess.com/analysis-board-editor and putting in the PGN. I'm not sure if you can go beyond a once-per-day quick analysis if you're not a premium member, though. And since we can't mention competing sites on here, I would suggest Googling "PGN analysis" or something similar to find easy solutions.

This has nothing to do with anything the guy is asking.

He's asking what engine they use on chess.com for post game analysis. 

I was assuming that the player was asking for how to import games (since the engine name is clearly labelled on the analysis board) - that's PGN, which you can c+p into any engine for analysis. 

I assumed that he/she just pressed the "analyze" button without knowing anything about PGN, getting the computer analysis of finished games without PGN. 

Where is the engine name labelled on the chess.com analysis board? I can't find it anywhere. 

it uses stockfish, to be exact stockfish.js

it runs in browser client-side, so your hardware powers it. Other websites, likes lichess (not an ad) uses very similar configuration.

https://stockfishchess.org/

https://github.com/exoticorn/stockfish-js

there are other free UCI compatible engines.

On a finished game, the "analysis board" option automatically loads and names the chess engine.

Oh, I've never seen that before, and I'm sure neither has the OP. 

He's been here for 6 years - that's 2 more than me...

Same board can be found in: Learn > Analysis 

@Cherub_Enjel wouldn't you want to have a shot at my puzzle?

I did try the puzzle! The first move was the important one though (only winning move), because although the 2nd move was cool, there were also multiple 2nd moves that also won the game (which I would have played in a real game, because it's less risky that I miscalculated). 

Decent puzzle overall though

Thanks, that 2.Rf5 will haunt me for a while, damn it is so beyond me...

Stockfish 8 is also part of the excellent freebie Lucas Chess, which is here:

http://www-lucaschess.rhcloud.com/index.html

Lucas chess includes a great analysis mode, where Stockfish 8 is the best to use, and also a lot of engines to play against and has tweaked many of them so you get a tremendous range of playing strengths as well as personalities that are aggressive, defensive, reckless, solid, etc.

Stockfish 8 64 bit can be downloaded from here (in the Stockfish 8 for Windows zip):

https://stockfishchess.org/download/

I added it as an external engine to Lucas Chess, as it should run slightly faster than the 32 bit version that is built-in to Lucas Chess.

Mate in 14, that's got some computer power.

The current website has only been the default since November 2016.

I'm sure most chess DB programs and some built primarily for analysis can do what you want.

I use SCID vs PC and Stockfish, both free. To get the full score graph there, you have to have the engine score every move. It also isn't a window/panel open by fefault in the program.