GPT-5.3 Instant vs Mistral Large 3

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

GPT-5.3 Instant is clearly ahead on the aggregate, 87 to 61. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.3 Instant's sharpest advantage is in coding, where it averages 78.7 against 41. The single biggest benchmark swing on the page is SWE-bench Pro, 83 to 42.

GPT-5.3 Instant is also the more expensive model on tokens at $1.75 input / $14.00 output per 1M tokens, versus $2.00 input / $6.00 output per 1M tokens for Mistral Large 3. That is roughly 2.3x on output cost alone. GPT-5.3 Instant is the reasoning model in the pair, while Mistral Large 3 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.

Quick Verdict

Pick GPT-5.3 Instant if you want the stronger benchmark profile. Mistral Large 3 only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

GPT-5.3 Instant

GPT-5.3 Instant

82.9

Mistral Large 3

52.5

86
Terminal-Bench 2.0
52
82
BrowseComp
58
80
OSWorld-Verified
49

Coding

GPT-5.3 Instant

GPT-5.3 Instant

78.7

Mistral Large 3

41

88
HumanEval
68
76
SWE-bench Verified
45
75
LiveCodeBench
39
83
SWE-bench Pro
42

Multimodal & Grounded

GPT-5.3 Instant

GPT-5.3 Instant

95

Mistral Large 3

75.5

95
MMMU-Pro
75
95
OfficeQA Pro
76

Reasoning

GPT-5.3 Instant

GPT-5.3 Instant

94.2

Mistral Large 3

70.6

96
SimpleQA
73
94
MuSR
71
97
BBH
81
92
LongBench v2
67
94
MRCRv2
67

Knowledge

GPT-5.3 Instant

GPT-5.3 Instant

80.8

Mistral Large 3

57.1

99
MMLU
76
98
GPQA
75
96
SuperGPQA
73
94
OpenBookQA
71
89
MMLU-Pro
74
44
HLE
12
92
FrontierScience
67

Instruction Following

GPT-5.3 Instant

GPT-5.3 Instant

96

Mistral Large 3

83

96
IFEval
83

Multilingual

GPT-5.3 Instant

GPT-5.3 Instant

93.4

Mistral Large 3

78.8

96
MGSM
82
92
MMLU-ProX
77

Mathematics

GPT-5.3 Instant

GPT-5.3 Instant

97.2

Mistral Large 3

77.3

99
AIME 2023
76
99
AIME 2024
78
98
AIME 2025
77
95
HMMT Feb 2023
72
97
HMMT Feb 2024
74
96
HMMT Feb 2025
73
96
BRUMO 2025
75
98
MATH-500
80

Frequently Asked Questions

Which is better, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant is ahead overall, 87 to 61. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 83 and 42.

Which is better for knowledge tasks, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 57.1. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for coding in this comparison, averaging 78.7 versus 41. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for math in this comparison, averaging 97.2 versus 77.3. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for reasoning in this comparison, averaging 94.2 versus 70.6. Inside this category, MRCRv2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for agentic tasks in this comparison, averaging 82.9 versus 52.5. 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 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for multimodal and grounded tasks in this comparison, averaging 95 versus 75.5. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for instruction following in this comparison, averaging 96 versus 83. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.3 Instant or Mistral Large 3?

GPT-5.3 Instant has the edge for multilingual tasks in this comparison, averaging 93.4 versus 78.8. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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