Keywords: Software

EGF-Calc is a freeware tool for windows, programmed by CBlue for calculating EGF ratings and winning probabilities. Either for single games you play or for tournaments where you participated.

You can download the latest version here: [ext] EGF-Calc v1.4c.

v1.4c - Increased GoR limit from 2700 to 3500. (18 December 2004)

v1.4b - Fixed a glitch in Jigo rating calculation.

v1.4a - Minor info text improvements.

v1.4 - The program now additionally tells you the winning probabilities for two players of specific ranking if they play each other (without handicap).

v1.3 - Minor GUI improvements. Corrected a mistake in tournament mode calculations.

v1.2 - Added a 'Tool Mode' for the fun of it, which lets you find out approximated winning quotes and the amount of games you need in order to achieve a certain rating.

v1.1 - Fixed a rounding issue. Tournament Mode working.

v1.0 - Initial release.

tderz: Many thanks for your nice tool, CBlue(?). Could you elaborate on the factor 0.014 with the coment "Balance dan regions. Don't change!" in your program. Could you

  • i) put your formula into the "info" screen and
  • ii) explain the "EGF reduces total HC bonus by 50, so winning expectancies might be off"-comment?

Many thanks in advance.

Is the parameter 0.014 of your program similar to the constant C (=30) in this link?: cf. [ext] GoBase's introduction to the elo rating system Can I not amend this value (there is an entry field) and why should I not?

CBlue: Sorry it has taken so long for replying.

  • i) as the program's info box says, the formulas are taken from the official website of the european go federation. The 0.014 factor is from that website too, the EGF uses it. It is very hardly noticable. I do not know why they decided to put it in. It's not similar to C in that link. You can of course change it, or remove it. I made it editable in case the EGF decides to change it.
  • ii) Yes this might need more explanation: If you get handicap stones, you might assume that each stone corresponds to 1 rank. And in the EGF, 1 rank corresponds to 100 points difference. However, the EGF formula says that you have to subtract 50 from the total amount of handicap stones before you calculate. Example: 5 handicap stones would lead to 500 points added to the weaker player's rank in the following calculation, but in fact the number 450 is used, since the EGF says to subtract 50 from the total HC bonus. Again I do not know why they decided this.

tderz: CBlue, you programmed i). If not C in the Elo-formula, what is it then in the formula?

ii) is easier to understand:

  • B+sente-komi is supposed to be even for evenly strong players;
  • komi is therefore(?) estimated worth half a move.
  • Now, if there is a 1 (n) grade difference, Black gets 1 (n) handicap stones, but no komi.
  • If the grade difference is 1 Black simply starts (no komi).
  • If the difference is n>1 White usually moves first.
  • Hence, I conclude that in handicap games with H= 2...9, White has the advantage of normally not giving komi but having sente.
  • Saving komi means having 1/2 move or 1/2 grade advantage.

Hope my reasoning is correct.

Rodival: CBlue, may I ask you how do you understood this EGF page info:

  • SE(A) + SE(B) = 1 - e

Knowing that the previous calculus gives se(A) and se(B) with se(A)+se(B)=1, (B is the higher player)
Should we compute:

  • SE(A):= se(A)
  • SE(B):= (1 - e) - SE(A)


  • SE(A):= (1 - e) * se(A)
  • SE(B):= (1 - e) * se(B)

Maybe my question is a little bit silly but I'm not a good enought mathematician to deal with those possibilities.

EGF-Calc last edited by velobici on March 4, 2008 - 00:20
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