GPT-5.3 Codex vs Ministral 3 3B (Reasoning)

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

GPT-5.3 Codex is clearly ahead on the aggregate, 89 to 31. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.3 Codex's sharpest advantage is in coding, where it averages 87.3 against 7.2. The single biggest benchmark swing on the page is SWE-bench Pro, 90 to 6.

GPT-5.3 Codex is also the more expensive model on tokens at $2.50 input / $10.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Ministral 3 3B (Reasoning). That is roughly Infinityx on output cost alone. GPT-5.3 Codex gives you the larger context window at 400K, compared with 128K for Ministral 3 3B (Reasoning).

Quick Verdict

Pick GPT-5.3 Codex if you want the stronger benchmark profile. Ministral 3 3B (Reasoning) only becomes the better choice if you want the cheaper token bill.

Agentic

GPT-5.3 Codex

GPT-5.3 Codex

88.1

Ministral 3 3B (Reasoning)

34

90
Terminal-Bench 2.0
33
88
BrowseComp
37
86
OSWorld-Verified
33

Coding

GPT-5.3 Codex

GPT-5.3 Codex

87.3

Ministral 3 3B (Reasoning)

7.2

95
HumanEval
16
85
SWE-bench Verified
9
85
LiveCodeBench
8
90
SWE-bench Pro
6

Multimodal & Grounded

GPT-5.3 Codex

GPT-5.3 Codex

91.3

Ministral 3 3B (Reasoning)

30.4

89
MMMU-Pro
25
94
OfficeQA Pro
37

Reasoning

GPT-5.3 Codex

GPT-5.3 Codex

93.7

Ministral 3 3B (Reasoning)

35.3

95
SimpleQA
26
93
MuSR
26
98
BBH
63
92
LongBench v2
37
93
MRCRv2
40

Knowledge

GPT-5.3 Codex

GPT-5.3 Codex

80.3

Ministral 3 3B (Reasoning)

25.2

99
MMLU
25
97
GPQA
24
95
SuperGPQA
22
93
OpenBookQA
20
90
MMLU-Pro
49
44
HLE
1
90
FrontierScience
29

Instruction Following

GPT-5.3 Codex

GPT-5.3 Codex

93

Ministral 3 3B (Reasoning)

68

93
IFEval
68

Multilingual

GPT-5.3 Codex

GPT-5.3 Codex

92.8

Ministral 3 3B (Reasoning)

59.7

96
MGSM
61
91
MMLU-ProX
59

Mathematics

GPT-5.3 Codex

GPT-5.3 Codex

97.7

Ministral 3 3B (Reasoning)

40.9

99
AIME 2023
27
99
AIME 2024
29
98
AIME 2025
28
95
HMMT Feb 2023
23
97
HMMT Feb 2024
25
96
HMMT Feb 2025
24
96
BRUMO 2025
26
99
MATH-500
59

Frequently Asked Questions

Which is better, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex is ahead overall, 89 to 31. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 90 and 6.

Which is better for knowledge tasks, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for knowledge tasks in this comparison, averaging 80.3 versus 25.2. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for coding in this comparison, averaging 87.3 versus 7.2. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for math in this comparison, averaging 97.7 versus 40.9. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for reasoning in this comparison, averaging 93.7 versus 35.3. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for agentic tasks in this comparison, averaging 88.1 versus 34. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for multimodal and grounded tasks in this comparison, averaging 91.3 versus 30.4. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for instruction following in this comparison, averaging 93 versus 68. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.3 Codex or Ministral 3 3B (Reasoning)?

GPT-5.3 Codex has the edge for multilingual tasks in this comparison, averaging 92.8 versus 59.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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