benchlm.ai

Gemini 2.5 Flash 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 41 (44 point difference).GPT-5.3 Codex wins 4 out of 4 categories.

Gemini 2.5 Flash

CreatorGoogle
TypeProprietary
Context1M
Score41

GPT-5.3 Codex

CreatorOpenAI
TypeProprietary
Context400K
Score85

Knowledge

GPT-5.3 Codex

Gemini 2.5 Flash

47.8

GPT-5.3 Codex

96

50
MMLU
99
49
GPQA
97
47
SuperGPQA
95
45
OpenBookQA
93

Coding

GPT-5.3 Codex

Gemini 2.5 Flash

42

GPT-5.3 Codex

95

42
HumanEval
95

Mathematics

GPT-5.3 Codex

Gemini 2.5 Flash

49

GPT-5.3 Codex

97.1

50
AIME 2023
99
52
AIME 2024
99
51
AIME 2025
98
46
HMMT Feb 2023
95
48
HMMT Feb 2024
97
47
HMMT Feb 2025
96
49
BRUMO 2025
96

Reasoning

GPT-5.3 Codex

Gemini 2.5 Flash

47

GPT-5.3 Codex

94

48
SimpleQA
95
46
MuSR
93

Frequently Asked Questions

Which is better, Gemini 2.5 Flash or GPT-5.3 Codex?

GPT-5.3 Codex scores higher overall with 85 vs 41, a difference of 44 points across all benchmarks.

Which is better for knowledge tasks, Gemini 2.5 Flash or GPT-5.3 Codex?

GPT-5.3 Codex leads in knowledge tasks with an average score of 96 vs 47.8.

Which is better for coding, Gemini 2.5 Flash or GPT-5.3 Codex?

GPT-5.3 Codex leads in coding with an average score of 95 vs 42.

Which is better for math, Gemini 2.5 Flash or GPT-5.3 Codex?

GPT-5.3 Codex leads in math with an average score of 97.1 vs 49.

Which is better for reasoning, Gemini 2.5 Flash or GPT-5.3 Codex?

GPT-5.3 Codex leads in reasoning with an average score of 94 vs 47.

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