benchlm.ai

Claude Sonnet 4.6 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 80 (5 point difference).GPT-5.3 Codex wins 1 out of 4 categories.

Claude Sonnet 4.6

CreatorAnthropic
TypeProprietary
Context1M
Score80

GPT-5.3 Codex

CreatorOpenAI
TypeProprietary
Context400K
Score85

Knowledge

Tie

Claude Sonnet 4.6

96

GPT-5.3 Codex

96

99
MMLU
99
97
GPQA
97
95
SuperGPQA
95
93
OpenBookQA
93

Coding

GPT-5.3 Codex

Claude Sonnet 4.6

93

GPT-5.3 Codex

95

93
HumanEval
95

Mathematics

Tie

Claude Sonnet 4.6

97.1

GPT-5.3 Codex

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

Tie

Claude Sonnet 4.6

94

GPT-5.3 Codex

94

95
SimpleQA
95
93
MuSR
93

Frequently Asked Questions

Which is better, Claude Sonnet 4.6 or GPT-5.3 Codex?

GPT-5.3 Codex scores higher overall with 85 vs 80, a difference of 5 points across all benchmarks.

Which is better for knowledge tasks, Claude Sonnet 4.6 or GPT-5.3 Codex?

Claude Sonnet 4.6 and GPT-5.3 Codex are tied for knowledge tasks with average scores of 96.

Which is better for coding, Claude Sonnet 4.6 or GPT-5.3 Codex?

GPT-5.3 Codex leads in coding with an average score of 95 vs 93.

Which is better for math, Claude Sonnet 4.6 or GPT-5.3 Codex?

Claude Sonnet 4.6 and GPT-5.3 Codex are tied for math with average scores of 97.1.

Which is better for reasoning, Claude Sonnet 4.6 or GPT-5.3 Codex?

Claude Sonnet 4.6 and GPT-5.3 Codex are tied for reasoning with average scores of 94.

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