benchlm.ai

Claude 4.1 Opus Thinking vs GPT-5.3 Codex

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

Quick Verdict

GPT-5.3 Codex wins overall with a score of 85 vs 29 (56 point difference).GPT-5.3 Codex wins 4 out of 4 categories.

Claude 4.1 Opus Thinking

CreatorAnthropic
TypeProprietary
Context200K
Score29

GPT-5.3 Codex

CreatorOpenAI
TypeProprietary
Context400K
Score85

Knowledge

GPT-5.3 Codex

Claude 4.1 Opus Thinking

35.8

GPT-5.3 Codex

96

38
MMLU
99
37
GPQA
97
35
SuperGPQA
95
33
OpenBookQA
93

Coding

GPT-5.3 Codex

Claude 4.1 Opus Thinking

30

GPT-5.3 Codex

95

30
HumanEval
95

Mathematics

GPT-5.3 Codex

Claude 4.1 Opus Thinking

37

GPT-5.3 Codex

97.1

38
AIME 2023
99
40
AIME 2024
99
39
AIME 2025
98
34
HMMT Feb 2023
95
36
HMMT Feb 2024
97
35
HMMT Feb 2025
96
37
BRUMO 2025
96

Reasoning

GPT-5.3 Codex

Claude 4.1 Opus Thinking

35

GPT-5.3 Codex

94

36
SimpleQA
95
34
MuSR
93

Frequently Asked Questions

Which is better, Claude 4.1 Opus Thinking or GPT-5.3 Codex?

GPT-5.3 Codex scores higher overall with 85 vs 29, a difference of 56 points across all benchmarks.

Which is better for knowledge tasks, Claude 4.1 Opus Thinking or GPT-5.3 Codex?

GPT-5.3 Codex leads in knowledge tasks with an average score of 96 vs 35.8.

Which is better for coding, Claude 4.1 Opus Thinking or GPT-5.3 Codex?

GPT-5.3 Codex leads in coding with an average score of 95 vs 30.

Which is better for math, Claude 4.1 Opus Thinking or GPT-5.3 Codex?

GPT-5.3 Codex leads in math with an average score of 97.1 vs 37.

Which is better for reasoning, Claude 4.1 Opus Thinking or GPT-5.3 Codex?

GPT-5.3 Codex leads in reasoning with an average score of 94 vs 35.

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