benchlm.ai

GPT-5.1-Codex-Max vs Kimi K2.5 (Reasoning)

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 71 (6 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 (Reasoning)

CreatorMoonshot AI
TypeOpen Weight
Context128K
Score71

Knowledge

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

95

Kimi K2.5 (Reasoning)

89

98
MMLU
92
96
GPQA
90
94
SuperGPQA
88
92
OpenBookQA
86

Coding

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

94

Kimi K2.5 (Reasoning)

84

94
HumanEval
84

Mathematics

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

97.1

Kimi K2.5 (Reasoning)

93

99
AIME 2023
94
99
AIME 2024
96
98
AIME 2025
95
95
HMMT Feb 2023
90
97
HMMT Feb 2024
92
96
HMMT Feb 2025
91
96
BRUMO 2025
93

Reasoning

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max

93

Kimi K2.5 (Reasoning)

87

94
SimpleQA
88
92
MuSR
86

Frequently Asked Questions

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

GPT-5.1-Codex-Max scores higher overall with 77 vs 71, a difference of 6 points across all benchmarks.

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

GPT-5.1-Codex-Max leads in knowledge tasks with an average score of 95 vs 89.

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

GPT-5.1-Codex-Max leads in coding with an average score of 94 vs 84.

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

GPT-5.1-Codex-Max leads in math with an average score of 97.1 vs 93.

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

GPT-5.1-Codex-Max leads in reasoning with an average score of 93 vs 87.

Related Comparisons

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