Now, since Codechef has announced Integral Problem Difficulty ratings, I have some questions:

**How is Problem Difficulty Rating calculated on Codechef?**

(For instance, in Codeforces, it is calculated based on how many users were able to solve it in the contest.)

**How does CodeChef Problem Difficulty Rating compare with Codeforces? What is approx mapping?**

(Ex: What would be the difficulty rating of a problem on Codeforces, whose difficulty rating on CodeChef is 2441 ?)

(I guess that mapping may be like

Codeforces_Rating(x) == Codechef_Rating(x) — kwhere k is like 200-300 or something. But I am not sure.)

**What is the basic implication of Codechef rating?**

(For instance, in Codeforces, *Approximately this means that if the rating of the problem is equal to yours, then on a typical round you would solve the problem with a probability of 0.5.*

Source : https://mirror.codeforces.com/blog/entry/62865 )

For Codeforces problem difficulty ratings, there are many blogs like https://mirror.codeforces.com/blog/entry/46304,

but there are none for CodeChef. That is why I resorted to asking about it here.

https://www.codechef.com/practice has both a tool tip and a "About Difficulty Rating" in the "Problem Difficulty Rating" section, which links you to https://blog.codechef.com/2022/02/25/exciting-updates-for-february-2022:

"It is calculated in such a way that if a problem’s difficulty rating is X, then a user whose CodeChef rating is X has a 50% chance of solving that problem in a contest."

The implementation is similar, but more similar to kenkoooo's than to CF's.

It’s probably more like 500+, my friend is 5 stars on codechef but pupil on codeforces, idk ? and lots of contests on both sites

Well, I am specialist here, but only 3* (about to touch 4*) on codeforces.

My Codechef handle https://www.codechef.com/users/nitinkumar1238