TOP 20:
# PLAYER : RATING ERROR POINTS PLAYED (%) 1 Stockfish 18dev_26010611 : 3874 12 896.5 1520 59.0% 2 Stockfish 17.1 : 3858 9 11183.0 17690 63.2% 3 Reckless 0.9-dev-0dd5b9ac : 3846 12 1057.5 1900 55.7% 4 PlentyChess 7.0.29 : 3837 12 1530.5 3070 49.9% 5 Obsidian 16.14 : 3833 12 1473.0 2660 55.4% 6 Alexandria 8.1.12 : 3810 13 1375.0 2660 51.7% 7 Clover 9.1 : 3793 13 1137.0 2280 49.9% 8 Lc0 0.31.2 BT3-7464000 1650m : 3788 20 184.5 390 47.3% 9 Viridithas 19.0.0 : 3787 10 1119.5 2280 49.1% 10 Berserk 13 : 3783 8 8229.5 16068 51.2% 11 Caissa 1.24 : 3782 10 1852.0 3800 48.7% 12 Quanticade 3.0 : 3778 13 763.0 1520 50.2% 13 Integral 7.0 : 3777 11 1829.5 3800 48.1% 14 Horsie 1.1 : 3769 10 1508.5 3422 44.1% 15 Stormphrax 7.0 : 3757 12 1027.0 2280 45.0% 16 Uralochka 3.42a : 3752 13 697.5 1520 45.9% 17 Starzix 6.0 : 3746 11 888.5 1900 46.8% 18 Halogen 15 : 3741 12 959.0 2280 42.1% 19 pawnocchio 1.8.1 : 3736 13 596.0 1520 39.2% 20 RubiChess 20240817 : 3734 11 1145.0 2660 43.0%
Updates:
Tested Stockfish 18dev_26010611.
Click here for the complete rating list:
The rating list – updated as of 16/01/2026 – is calculated with Ordo and was obtained under the following assumptions.
- The Elo rating of Rebel 6 UCI (1994) is fixed at 2450 points, which serves as an “anchor” for all others. This score is the average value of the results obtained by the original version of the engine in various matches against human GMs in the early 90s, derived from various official or unofficial sources (Talkchess.com, Rebel13.nl, computerchessuk.com, various forums…).
- Several electronic chessboards have been added whose strength in terms of Elo obtained through matches with humans is fairly well known. In this way, the rating list should provide engine scores that are more easily comparable with human ones. The electronic chessboards were emulated with CB-Emu, and made to play against several UCI and Winboard engines of similar strength.
- The time per game was set to 40/120′ repeated, reparameterized to the processing speed of a Pentium 90. The execution speed of the latter was emulated, and through various benchmarks done in the past on real P90 machines, I tried to obtain a value as close as possible to reality. Consequently, on modern PCs the actual time per game was 40/125” or 40/130” (seconds) depending on the PC used for the test, comparable to other blitz tests found on the net. For some engines, such as Chess Titans, it was not possible to define a game time; for this reason, I have indicated the characteristics of the CPU on which it was tested.
- The opening suite consists of 190 different positions, repeated for each engine (each engine played the same opening both as white and black). For older engines, not equipped with a UCI or XBoard interface (such as the 1988 version of BattleChess), I manually reproduced the various moves suggested by the programs. Also for these engines, as for all the others, the playing time was reparameterized to the performance of a Pentium 90. For this reason, the games of these engines are few compared to the total, and based on random selections of the 190 openings. The opening suite can be downloaded here.
- All the chess engines used are freely available on the net, with the exception of commercial programs that I purchased years ago, and are limited to using only one CPU core.
- In the “Top 10”, I have not included past versions of Stockfish, nor engines derived from it (such as Shashchess). In the complete rating list, I have also included past versions of Stockfish for comparison.
- The main goal of this rating list, made for my exclusive enjoyment, was both to determine the playing level of modern engines compared to past ones, but also to evaluate the actual playing strength of many programs that I loved in my youth (the aforementioned Battlechess, for example).