Model comparison

Claude Sonnet 5.5 vs Mistral Medium 3.5

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 40.2 on the Noometry Index.

Last verified October 10, 2026. 16 shared benchmarks.

Claude Sonnet 5.5 Anthropic

61.9

Rank #10 Confirmed

Mistral Medium 3.5

Mistral AI

40.2

Rank #152 Confirmed

Summary

They share 16 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 9 categories and Mistral Medium 3.5 in 0 categories; 9 gaps are clear of the uncertainty.
The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 39.1.
The biggest single-benchmark swing is NYT Connections (extended): 80.5% for Claude Sonnet 5.5 and 12.9% for Mistral Medium 3.5.
Mistral Medium 3.5 is cheaper at $1.50 / $7.50 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
Claude Sonnet 5.5 accepts more context: 1M tokens versus 262K.
Mistral Medium 3.5 has downloadable open weights; the other is API-only.

Side by side

Claude Sonnet 5.5 and Mistral Medium 3.5 specifications
	Claude Sonnet 5.5	Mistral Medium 3.5
Provider	Anthropic	Mistral AI
Noometry Index	61.9	40.2
Released	2026-09-28	—
Weights	Proprietary	Open
Context window	1M	262K
Max output	128K	210K
Input $ / M tokens	$2	$1.50
Output $ / M tokens	$10	$7.50
Results tracked	32	22

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Category by category

Coding Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 67.3 (#6), Mistral Medium 3.5: 36.0 (#213)

Coding benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena WebDev	1774	1264
LMArena Coding	1513	1461
FrontierCode	52.1%	—
CursorBench	55.5%	—
FrontierSWE	61.9%	—
SciCode	61%	—
ALE-Bench	1,819	—

Agentic & Tool Use Not comparable

Claude Sonnet 5.5: 45.0 (#16), Mistral Medium 3.5: —

Agentic & Tool Use benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
APEX-Agents	75.5%	—

Reasoning Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 54.0 (#28), Mistral Medium 3.5: 17.3 (#295)

Reasoning benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
NYT Connections (extended)	80.5%	12.9%
LMArena Hard Prompts	1495	1436
Epoch Capabilities Index	165.03	141.35
Kagi LLM Benchmark	—	41.4%
CritPt	31.4%	—
Mystery Game Puzzles	65%	—

Math Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 87.9 (#6), Mistral Medium 3.5: 39.1 (#113)

Math benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena Math	1510	1431
FrontierMath (Tiers 1-3)	88.8%	—
FrontierMath Tier 4	80.5%	—
OTIS Mock AIME 2024-2025	100%	—
ProofBench	100%	—
FrontierMath Erdős	2.9%	—

Knowledge Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 66.0 (#12), Mistral Medium 3.5: 40.0 (#126)

Knowledge benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena Expert	1540	1432
GPQA Diamond	95.6%	—
SimpleQA Verified	46.5%	—

Multimodal Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 51.5 (#6), Mistral Medium 3.5: 38.3 (#65)

Multimodal benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena Vision	1289	1223
Furniture Assembly	75%	—

Multilingual Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 55.3 (#30), Mistral Medium 3.5: 51.9 (#100)

Multilingual benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena Non-English	1452	1404
LMArena Chinese	1522	1442
LMArena Russian	1451	1395
LMArena French	—	1448
LMArena German	—	1451
LMArena Korean	—	1385
LMArena Spanish	—	1409

Instruction Following Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 78.3 (#11), Mistral Medium 3.5: 74.6 (#90)

Instruction Following benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena Instruction Following	1495	1415

Long Context Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 45.9 (#28), Mistral Medium 3.5: 43.2 (#103)

Long Context benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena Longer Query	1498	1415

Writing & Preference Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 66.0 (#40), Mistral Medium 3.5: 58.5 (#117)

Writing & Preference benchmarks
Benchmark	Claude Sonnet 5.5	Mistral Medium 3.5
LMArena Text	1471	1421
LMArena Creative Writing	1465	1374
LMArena Multi-Turn	1474	1423
EQ-Bench 4	—	993

Frequently asked questions

Is Claude Sonnet 5.5 better than Mistral Medium 3.5?

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 40.2 on the Noometry Index.

Which is cheaper, Claude Sonnet 5.5 or Mistral Medium 3.5?

Mistral Medium 3.5 is cheaper. It lists at $1.50 per million input tokens and $7.50 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.

Is Claude Sonnet 5.5 or Mistral Medium 3.5 better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 36.0 in the Noometry coding category.

Which has the bigger context window?

Claude Sonnet 5.5 does, with 1M tokens against 262K.

How many benchmarks do Claude Sonnet 5.5 and Mistral Medium 3.5 share?

16 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and Mistral Medium 3.5 has 22.