Model comparison

Mistral Medium 3.1 vs o3

o3 is the stronger model overall, scoring 47.5 to 31.9 on the Noometry Index. Mistral Medium 3.1 costs 4.4× less per token, which makes it the better buy when o3's lead doesn't matter for your workload.

Last verified October 11, 2026. 1 shared benchmarks.

Mistral Medium 3.1

Mistral AI

31.9

Rank #266 Reported

o3 OpenAI

47.5

Rank #61 Confirmed

Summary

They share 1 benchmark with published results for both. Mistral Medium 3.1 scores higher in 0 categories and o3 in 2 categories; 2 gaps are clear of the uncertainty.
The widest gap is in reasoning, where o3 leads 32.0 to 10.6.
Mistral Medium 3.1 is cheaper at $0.40 / $2 per million input/output tokens, against $2 / $8 for o3.
o3 accepts more context: 200K tokens versus 131K.

Side by side

Mistral Medium 3.1 and o3 specifications
	Mistral Medium 3.1	o3
Provider	Mistral AI	OpenAI
Noometry Index	31.9	47.5
Released	—	2025-04-16
Weights	Proprietary	Proprietary
Context window	131K	200K
Max output	105K	100K
Input $ / M tokens	$0.40	$2
Output $ / M tokens	$2	$8
Results tracked	3	63

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Category by category

Coding Not comparable

Mistral Medium 3.1: —, o3: 46.8 (#64)

Coding benchmarks
Benchmark	Mistral Medium 3.1	o3
SWE-bench Verified	—	62.3%
SWE-bench Verified (bash only)	—	58.4%
Aider Polyglot	—	81.3%
GSO	—	8.8%
WeirdML	—	52.4%
LMArena Coding	—	1408
CadEval	—	74%
ALE-Bench	—	933.55

Agentic & Tool Use Not comparable

Mistral Medium 3.1: —, o3: 34.5 (#44)

Agentic & Tool Use benchmarks
Benchmark	Mistral Medium 3.1	o3
Berkeley Function Calling Leaderboard	—	63%
GDPval	—	30.8%
DeepResearch Bench	—	45.2%
OSWorld	—	23%
LMArena Search	—	1144
METR Time Horizons	—	65.4%

Reasoning o3 leads

Mistral Medium 3.1: 10.6 (#341), o3: 32.0 (#78)

Reasoning benchmarks
Benchmark	Mistral Medium 3.1	o3
ARC-AGI-2	—	6.5%
SimpleBench	—	53.1%
Kagi LLM Benchmark	—	67.6%
NYT Connections (extended)	6.5%	—
ARC-AGI-1	—	60.8%
CritPt	—	1.4%
Chess Puzzles	—	38%
EnigmaEval	—	13.1%
Thematic Generalization	20.3%	—
LMArena Hard Prompts	—	1402
Mystery Game Puzzles	—	29%
DTBench	—	84.8%
LMCA	—	39.7%
Epoch Capabilities Index	—	146.86
ForecastBench	—	62.5

Math Not comparable

Mistral Medium 3.1: —, o3: 50.2 (#58)

Math benchmarks
Benchmark	Mistral Medium 3.1	o3
FrontierMath (Tiers 1-3)	—	33.3%
OTIS Mock AIME 2024-2025	—	84.4%
Omni-MATH	—	71.4%
LMArena Math	—	1426
MATH Level 5	—	97.8%
FrontierMath (Feb 2025 set)	—	18.7%
FrontierMath Tier 4 (v1)	—	2.1%

Knowledge Not comparable

Mistral Medium 3.1: —, o3: 54.6 (#52)

Knowledge benchmarks
Benchmark	Mistral Medium 3.1	o3
GPQA Diamond	—	81.8%
Humanity's Last Exam	—	20.3%
SimpleQA Verified	—	49.4%
MMLU-Pro	—	85.9%
Confabulations	—	14.4%
GPQA (HELM)	—	75.3%
LMArena Expert	—	1402

Multimodal Not comparable

Mistral Medium 3.1: —, o3: 41.4 (#36)

Multimodal benchmarks
Benchmark	Mistral Medium 3.1	o3
LMArena Vision	—	1214
GeoBench	—	74%
VPCT	—	52%

Multilingual Not comparable

Mistral Medium 3.1: —, o3: 51.7 (#105)

Multilingual benchmarks
Benchmark	Mistral Medium 3.1	o3
LMArena Non-English	—	1401
LMArena Chinese	—	1437
LMArena French	—	1430
LMArena German	—	1420
LMArena Japanese	—	1403
LMArena Korean	—	1370
LMArena Russian	—	1406
LMArena Spanish	—	1395

Instruction Following Not comparable

Mistral Medium 3.1: —, o3: 72.8 (#127)

Instruction Following benchmarks
Benchmark	Mistral Medium 3.1	o3
IFEval	—	86.9%
LMArena Instruction Following	—	1368

Long Context Not comparable

Mistral Medium 3.1: —, o3: 53.3 (#6)

Long Context benchmarks
Benchmark	Mistral Medium 3.1	o3
Fiction.LiveBench	—	88.9%
CL-bench	—	17.8%
LMArena Longer Query	—	1372

Writing & Preference o3 leads

Mistral Medium 3.1: 55.5 (#145), o3: 63.5 (#64)

Writing & Preference benchmarks
Benchmark	Mistral Medium 3.1	o3
EQ-Bench Creative Writing	1476	1676
LMArena Text	—	1410
LMArena Creative Writing	—	1359
Short-Story Creative Writing	—	83.9%
WildBench	—	86.1%
LMArena Multi-Turn	—	1405

Frequently asked questions

Is Mistral Medium 3.1 better than o3?

Which is cheaper, Mistral Medium 3.1 or o3?

Mistral Medium 3.1 is cheaper. It lists at $0.40 per million input tokens and $2 per million output tokens; o3 lists at $2 and $8.

Which has the bigger context window?

o3 does, with 200K tokens against 131K.

How many benchmarks do Mistral Medium 3.1 and o3 share?

1 benchmark has published results for both models. Mistral Medium 3.1 has 3 scored results on Noometry and o3 has 63.