Benchmark Almanac

Leipzig Benchmark

GPT-5.6 Sol Pro 91% leads since July 2026
Not in model cards

Models answer 100 research-level math questions with known answers, written by 49 mathematicians at a Max Planck Institute workshop in April and May 2026.

Two questions stayed unsolved after heavy-thinking runs in mid 2026, and one after the September 2026 re-run with tools. The questions are printed in the paper appendix.

Released
June 2026
Kind
Research mathematics
Level
Research frontier
Scored
Checked automatically
Answers
Short answer
Tasks
All public
Strongest model tested
GPT-6 Astra #3 on the capability index
Last model added
September 2026
Scores refreshed
November 11th, 2026

In the authors’ words

Between April 1 and May 15, 2026, a group of 49 mathematicians compiled a dataset of research-level mathematics questions with known answers. Most of the work was done during the three-day workshop Benchmarks in Leipzig with 35 participants at the Max Planck Institute for Mathematics in the Sciences in Leipzig, Germany. We present the resulting collection of 100 questions. We evaluated these questions in three stages: a single attempt by five state-of-the-art LLMs and their predecessors, followed by a 20-runs-per-model evaluation with three of these models, and finally a 3-run attempt with two heavy-thinking models. After Stage 1, 41 questions remained completely unsolved; after Stage 2, this count dropped to 16; and we concluded Stage 3 with only 2 unsolved questions. This demonstrates that the mathematical reasoning capabilities of LLMs are becoming impressive. In September 2026, we added a fourth stage in which the next generation of models attempted all 100 questions once more, after which only 1 question remains unsolved.

Abstract of Benchmarks in Leipzig (arXiv:2606.05818, CC0)
19
Models scored on its own leaderboard

2 models share the top score of 91% among models released by September 2026

Best score per model from the benchmark's own leaderboard, read on November 11th, 2026. Where a model ran with several settings or harnesses, we keep its best.

The newest model with a score here came out in September 2026, and nobody has tested a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:

  1. 1 GPT-5.6 Sol Pro max, web search, code 91%
  2. 2 GPT-6 Astra max, web search, code 91%
  3. 3 GPT-5.6 Sol max, web search, code 90%
  4. 4 GPT-6 Astra Pro max, web search, code 88%
  5. 5 GPT-6 Sol max, web search, code 86%
  6. 6 Claude Opus 5.5 high, web search, code 85%
  7. 7 Claude Fable 5.1 high, web search, code 79%
  8. 8 Claude Opus 5 high, web search, code 75%
  9. 9 GPT-5.5 xhigh, web search 44%
  10. 10 Gemini 3.8 Flash web search 41%
  11. 11 GPT-5.4 xhigh 28%
  12. 12 Gemini 3.1 Pro web search 15%
  13. 13 Gemini 3 Pro 14%
  14. 14 Claude Opus 4.6 14%
  15. 15 Claude Opus 4.7 13%
  16. 16 DeepSeek-V4-Pro web search 10%
  17. 17 DeepSeek-V3.2 8.00%
  18. 18 Grok 4.3 high, web search 6.00%
  19. 19 Grok 4.20 5.00%

Source: Official Leipzig Benchmark leaderboard

#ModelScoreSettingDateSource
1 GPT-5.6 Sol Pro 91% max, web search, code Jul 2026 Official leaderboard
2 GPT-6 Astra 91% max, web search, code Sep 2026 Official leaderboard
3 GPT-5.6 Sol 90% max, web search, code Jul 2026 Official leaderboard
4 GPT-6 Astra Pro 88% max, web search, code Sep 2026 Official leaderboard
5 GPT-6 Sol 86% max, web search, code Sep 2026 Official leaderboard
6 Claude Opus 5.5 85% high, web search, code Sep 2026 Official leaderboard
7 Claude Fable 5.1 79% high, web search, code Sep 2026 Official leaderboard
8 Claude Opus 5 75% high, web search, code Jul 2026 Official leaderboard
9 GPT-5.5 44% xhigh, web search Apr 2026 Official leaderboard
10 Gemini 3.8 Flash 41% web search Sep 2026 Official leaderboard
11 GPT-5.4 28% xhigh Mar 2026 Official leaderboard
12 Gemini 3.1 Pro 15% web search Feb 2026 Official leaderboard
13 Gemini 3 Pro 14% Nov 2025 Official leaderboard
14 Claude Opus 4.6 14% Feb 2026 Official leaderboard
15 Claude Opus 4.7 13% Apr 2026 Official leaderboard
16 DeepSeek-V4-Pro 10% web search Apr 2026 Official leaderboard
17 DeepSeek-V3.2 8.00% Dec 2025 Official leaderboard
18 Grok 4.3 6.00% high, web search Apr 2026 Official leaderboard
19 Grok 4.20 5.00% Feb 2026 Official leaderboard

2 models have held number one on the official leaderboard since its release in June 2026

Lab claims count from the day the card came out, independent runs from the model’s release.

OpenAI
Own leaderboard Passed 85% in Jul 2026, by GPT-5.6 Sol Pro

Source: Official Leipzig Benchmark leaderboard

GPT-5.6 Sol Pro on the official leaderboard passed 85% in July 2026

All the scores we have, one dot each, so a model tested at several settings appears more than once.

On the benchmark’s own leaderboard Best so far
0% 20% 40% 60% 80% 100% 2026 Near the ceiling (85%) GPT-5.6 Sol Pro GPT-5.5 GPT-5.4 Gemini 3.1 Pro Gemini 3 Pro 0% 20% 40% 60% 80% 100% 2026 Near the ceiling (85%) GPT-5.6 Sol Pro GPT-5.5

Source: Official Leipzig Benchmark leaderboard

No lab model card reports it yet

We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark.

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