benchlm.ai

GPT-5.1-Codex-Max vs Kimi K2.5

Side-by-side benchmark comparison across knowledge, coding, math, and reasoning.

Quick Verdict

GPT-5.1-Codex-Max wins overall with a score of 77 vs 62 (15 point difference).GPT-5.1-Codex-Max wins 4 out of 4 categories.

GPT-5.1-Codex-Max

CreatorOpenAI
TypeProprietary
Context400K
Score77

Kimi K2.5

CreatorMoonshot AI
TypeOpen Weight
Context128K
Score62

Knowledge

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

95

Kimi K2.5

74.8

98
MMLU
77
96
GPQA
76
94
SuperGPQA
74
92
OpenBookQA
72

Coding

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

94

Kimi K2.5

69

94
HumanEval
69

Mathematics

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

97.1

Kimi K2.5

76

99
AIME 2023
77
99
AIME 2024
79
98
AIME 2025
78
95
HMMT Feb 2023
73
97
HMMT Feb 2024
75
96
HMMT Feb 2025
74
96
BRUMO 2025
76

Reasoning

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

93

Kimi K2.5

73

94
SimpleQA
74
92
MuSR
72

Frequently Asked Questions

Which is better, GPT-5.1-Codex-Max or Kimi K2.5?

GPT-5.1-Codex-Max scores higher overall with 77 vs 62, a difference of 15 points across all benchmarks.

Which is better for knowledge tasks, GPT-5.1-Codex-Max or Kimi K2.5?

GPT-5.1-Codex-Max leads in knowledge tasks with an average score of 95 vs 74.8.

Which is better for coding, GPT-5.1-Codex-Max or Kimi K2.5?

GPT-5.1-Codex-Max leads in coding with an average score of 94 vs 69.

Which is better for math, GPT-5.1-Codex-Max or Kimi K2.5?

GPT-5.1-Codex-Max leads in math with an average score of 97.1 vs 76.

Which is better for reasoning, GPT-5.1-Codex-Max or Kimi K2.5?

GPT-5.1-Codex-Max leads in reasoning with an average score of 93 vs 73.

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