benchlm.ai

Gemini 3 Pro Deep Think 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 81 (4 point difference).GPT-5.3 Codex wins 1 out of 4 categories.

Gemini 3 Pro Deep Think

CreatorGoogle
TypeProprietary
Context2M
Score81

GPT-5.3 Codex

CreatorOpenAI
TypeProprietary
Context400K
Score85

Knowledge

Tie

Gemini 3 Pro Deep Think

96

GPT-5.3 Codex

96

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

Coding

GPT-5.3 Codex

Gemini 3 Pro Deep Think

91

GPT-5.3 Codex

95

91
HumanEval
95

Mathematics

Tie

Gemini 3 Pro Deep Think

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

Gemini 3 Pro Deep Think

94

GPT-5.3 Codex

94

95
SimpleQA
95
93
MuSR
93

Frequently Asked Questions

Which is better, Gemini 3 Pro Deep Think or GPT-5.3 Codex?

GPT-5.3 Codex scores higher overall with 85 vs 81, a difference of 4 points across all benchmarks.

Which is better for knowledge tasks, Gemini 3 Pro Deep Think or GPT-5.3 Codex?

Gemini 3 Pro Deep Think and GPT-5.3 Codex are tied for knowledge tasks with average scores of 96.

Which is better for coding, Gemini 3 Pro Deep Think or GPT-5.3 Codex?

GPT-5.3 Codex leads in coding with an average score of 95 vs 91.

Which is better for math, Gemini 3 Pro Deep Think or GPT-5.3 Codex?

Gemini 3 Pro Deep Think and GPT-5.3 Codex are tied for math with average scores of 97.1.

Which is better for reasoning, Gemini 3 Pro Deep Think or GPT-5.3 Codex?

Gemini 3 Pro Deep Think and GPT-5.3 Codex are tied for reasoning with average scores of 94.

Related Comparisons

Gemini 3 Pro Deep Think vs GPT-5.4Gemini 3 Pro Deep Think vs Gemini 3.1 ProGemini 3 Pro Deep Think vs Claude Opus 4.6Gemini 3 Pro Deep Think vs Grok 4.1Gemini 3 Pro Deep Think vs GPT-5.2Gemini 3 Pro Deep Think vs GPT-5.2-Codex