benchlm.ai

Claude Opus 4.5 vs GPT-5.1-Codex-Max

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

Quick Verdict

Claude Opus 4.5 wins overall with a score of 79 vs 77 (2 point difference).Claude Opus 4.5 wins 2 out of 4 categories.

Claude Opus 4.5

CreatorAnthropic
TypeProprietary
Context200K
Score79

GPT-5.1-Codex-Max

CreatorOpenAI
TypeProprietary
Context400K
Score77

Knowledge

Claude Opus 4.5

Claude Opus 4.5

96

GPT-5.1-Codex-Max

95

99
MMLU
98
97
GPQA
96
95
SuperGPQA
94
93
OpenBookQA
92

Coding

GPT-5.1-Codex-Max

Claude Opus 4.5

91

GPT-5.1-Codex-Max

94

91
HumanEval
94

Mathematics

Tie

Claude Opus 4.5

97.1

GPT-5.1-Codex-Max

97.1

99
AIME 2023
99
99
AIME 2024
99
98
AIME 2025
98
95
HMMT Feb 2023
95
97
HMMT Feb 2024
97
96
HMMT Feb 2025
96
96
BRUMO 2025
96

Reasoning

Claude Opus 4.5

Claude Opus 4.5

94

GPT-5.1-Codex-Max

93

95
SimpleQA
94
93
MuSR
92

Frequently Asked Questions

Which is better, Claude Opus 4.5 or GPT-5.1-Codex-Max?

Claude Opus 4.5 scores higher overall with 79 vs 77, a difference of 2 points across all benchmarks.

Which is better for knowledge tasks, Claude Opus 4.5 or GPT-5.1-Codex-Max?

Claude Opus 4.5 leads in knowledge tasks with an average score of 96 vs 95.

Which is better for coding, Claude Opus 4.5 or GPT-5.1-Codex-Max?

GPT-5.1-Codex-Max leads in coding with an average score of 94 vs 91.

Which is better for math, Claude Opus 4.5 or GPT-5.1-Codex-Max?

Claude Opus 4.5 and GPT-5.1-Codex-Max are tied for math with average scores of 97.1.

Which is better for reasoning, Claude Opus 4.5 or GPT-5.1-Codex-Max?

Claude Opus 4.5 leads in reasoning with an average score of 94 vs 93.

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