The table can be found here 8.1b
https://handbook.fide.com/chapter/B022017
Hi Malcolm,
As it happens, I created this webpage for the 4NCL which calculated the stats for all the players using FIDE ratings:-
https://4ncl.co.uk/pre2010/0405_stats.htm
Where I embedded the FIDE expected score formula table within my JavaScript code. The file was basically a flat database stored in text. It is over 12,000 lines of code (including data) and took 45 seconds to load the webpage and several people complained of errors. Anyway, now with the latest browsers it loads instantly.
So, what I did was found the difference between the two players, searched the table for the where the first occurrence of the first column being equal to or below the difference, the second column would be the upper limit (not actually required). Then, the third column was the expected score of the lower rated player, and the fourth the higher rated.
Table sample
0,3,0.50,0.50
4,10,0.49,0.51
11,17,0.48,0.52
...
518,559,0.03,0.97
560,619,0.02,0.98
620,735,0.01,0.99
With over 735 being 0.00 and 1.00, a win for the higher rated player.
That's the FIDE calculations, ECF may be different.
Hope that helps.
Cheers,
Paul Dupre