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Claude Sonnet 5.5 vs Mistral Medium 3.5

Updated October 21, 2026. 58 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Sonnet 5.5 Replace Mistral Medium 3.5
Claude Sonnet 5.5Anthropic
Coding
88.9
Overall
56.0
Output $/M
$10.00
58
Mistral Medium 3.5Mistral AI
Coding
9.2
Overall
14.2
Output $/M
$7.50
0
vs boards won of 58 shared

Decision reading

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 9.2 for Mistral Medium 3.5.

Pick Mistral Medium 3.5 when output tokens cost 1.3x less.

Model AClaude Sonnet 5.5Anthropic88.9/1002 independent benchmarksNo cost per solved taskModel BMistral Medium 3.5Mistral AI9.2/1001 independent benchmark$6.02 per solved task
Shared results
58
Claude Sonnet 5.5 only
37
Mistral Medium 3.5 only
22
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
Claude Sonnet 5.5 88.9 from 2 benchmarks, Mistral Medium 3.5 9.2 from 1 benchmark.
Widest category
Coding, 44.9 points apart on average over 10 shared benchmarks.
Widest single gap
ProofBench: Claude Sonnet 5.5 100.0% against Mistral Medium 3.5 9.0%, 91.0 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 5.5 $10.00 against Mistral Medium 3.5 $7.50 per million output tokens, 1.3x apart.
Context window
Claude Sonnet 5.5 takes 1M tokens, Mistral Medium 3.5 262K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryClaude Sonnet 5.5BarsMistral Medium 3.5Ties
Coding100
Intelligence20
Agentic work40
Reasoning60
Math30
Knowledge50
Web design60
General220
All shared boards580
CodingLike-for-likeFour of these boards feed the Vibe Coding Index100
Coding benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
LiveBench coding94.7%Not measuredOnly Claude Sonnet 5.5 measured
LMArena WebDev17681264Claude Sonnet 5.5
AA Coding IndexNot measured46.9Only Mistral Medium 3.5 measured
SWE-bench Verified (Vals AI)Not measured66.4%Only Mistral Medium 3.5 measured
Terminal-Bench 4 (Vals AI)64.1%Not measuredOnly Claude Sonnet 5.5 measured
Vibe Code Bench (Vals AI)92.4%2.9%Claude Sonnet 5.5
Code migration (Vals AI)69.8%5.1%Claude Sonnet 5.5
ProgramBench (Vals AI)6.5%Not measuredOnly Claude Sonnet 5.5 measured
IOI (Vals AI)83.1%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench 2.1 (Vals AI)83.2%39.0%Claude Sonnet 5.5
SWE-bench Multimodal (Vals AI)58.3%Not measuredOnly Claude Sonnet 5.5 measured
CyberBench (Vals AI)59.6%Not measuredOnly Claude Sonnet 5.5 measured
SciCode61.0%40.2%Claude Sonnet 5.5
Terminal-Bench Hard (Artificial Analysis run)Not measured33.3%Only Mistral Medium 3.5 measured
FrontierCode52.1%Not measuredOnly Claude Sonnet 5.5 measured
FrontierSWE61.9%Not measuredOnly Claude Sonnet 5.5 measured
ALE-Bench1819.1764.0Claude Sonnet 5.5
LMArena Text: coding15131460Claude Sonnet 5.5
LMArena Text: software and IT15041458Claude Sonnet 5.5
LMArena WebDev: React18171254Claude Sonnet 5.5
LMArena WebDev: HTML17411308Claude Sonnet 5.5
LMArena WebDev: from an image1737Not measuredOnly Claude Sonnet 5.5 measured
Neither model has a result on the other 16 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
AA Intelligence Index56.014.2Claude Sonnet 5.5
Epoch Capabilities Index166.2141.4Claude Sonnet 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index40
Agentic work benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
AA Agentic IndexNot measured7.0Only Mistral Medium 3.5 measured
Design Arena: agents building web apps1303Not measuredOnly Claude Sonnet 5.5 measured
Design Arena: agents building mobile apps1265Not measuredOnly Claude Sonnet 5.5 measured
Design Arena: spreadsheets1245Not measuredOnly Claude Sonnet 5.5 measured
LiveBench research83.6%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench browser84.0%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench long agentic78.8%Not measuredOnly Claude Sonnet 5.5 measured
SREBench (Vals AI)30.1%Not measuredOnly Claude Sonnet 5.5 measured
Finance Agent (Vals AI)58.1%32.1%Claude Sonnet 5.5
Tax Agent Bench (Vals AI)42.0%4.5%Claude Sonnet 5.5
Legal Research Bench (Vals AI)48.1%9.1%Claude Sonnet 5.5
Harvey's Legal Agent Benchmark (Vals AI)10.4%Not measuredOnly Claude Sonnet 5.5 measured
Excel Modeling Benchmark (Vals AI)75.7%11.2%Claude Sonnet 5.5
BioMysteryBench (Vals AI)81.1%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench-Science (Vals AI)47.1%Not measuredOnly Claude Sonnet 5.5 measured
Vals Science Index59.1%Not measuredOnly Claude Sonnet 5.5 measured
τ²-Bench TelecomNot measured94.2%Only Mistral Medium 3.5 measured
APEX-Agents75.5%Not measuredOnly Claude Sonnet 5.5 measured
SpireClimb1.3%Not measuredOnly Claude Sonnet 5.5 measured
Vending-Bench 2$11,165Not measuredOnly Claude Sonnet 5.5 measured
Neither model has a result on the other 19 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index60
Reasoning benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
GPQA DiamondNot measured34.9%Only Mistral Medium 3.5 measured
LiveBench reasoning91.6%Not measuredOnly Claude Sonnet 5.5 measured
MysteryMechanism (Vals AI)49.1%Not measuredOnly Claude Sonnet 5.5 measured
GPQA Diamond (Artificial Analysis run)Not measured74.8%Only Mistral Medium 3.5 measured
Humanity's Last Exam (Artificial Analysis run)55.0%13.8%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)95.6%Not measuredOnly Claude Sonnet 5.5 measured
Chess puzzles59.0%Not measuredOnly Claude Sonnet 5.5 measured
Mystery game puzzles65.0%Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text: hard prompts14941436Claude Sonnet 5.5
LMArena Text: expert15311432Claude Sonnet 5.5
LMArena Text: hard prompts in English15021445Claude Sonnet 5.5
LMArena Vision: diagrams13291254Claude Sonnet 5.5
LMArena Vision: homework13311230Claude Sonnet 5.5
Neither model has a result on the other 8 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index30
Math benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
OTIS Mock AIME100.0%Not measuredOnly Claude Sonnet 5.5 measured
FrontierMath, tiers 1 to 388.8%Not measuredOnly Claude Sonnet 5.5 measured
FrontierMath, tier 480.5%Not measuredOnly Claude Sonnet 5.5 measured
ProofBench100.0%9.0%Claude Sonnet 5.5
LMArena Text: math14971431Claude Sonnet 5.5
LMArena Text: mathematical work15101440Claude Sonnet 5.5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index50
Knowledge benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
MMLU ProNot measured75.3%Only Mistral Medium 3.5 measured
CaseLaw (Vals AI)Not measured44.2%Only Mistral Medium 3.5 measured
CorpFin (Vals AI)Not measured58.8%Only Mistral Medium 3.5 measured
TaxEval (Vals AI)Not measured68.0%Only Mistral Medium 3.5 measured
MortgageTax (Vals AI)Not measured28.9%Only Mistral Medium 3.5 measured
MedCode (Vals AI)52.9%33.8%Claude Sonnet 5.5
SimpleQA Verified46.5%Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text: science14831428Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641409Claude Sonnet 5.5
LMArena Text: legal and government14831437Claude Sonnet 5.5
LMArena Text: business and finance14681426Claude Sonnet 5.5
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
Design Arena: websites13261142Claude Sonnet 5.5
Design Arena: UI components13671079Claude Sonnet 5.5
Design Arena: game dev14691079Claude Sonnet 5.5
Design Arena: data viz13891120Claude Sonnet 5.5
Design Arena: 3D14581061Claude Sonnet 5.5
Design Arena: all code categories13641122Claude Sonnet 5.5
Design Arena: SVGNot measured949Only Mistral Medium 3.5 measured
Design Arena: ASCII artNot measured1062Only Mistral Medium 3.5 measured
LiveBench design85.0%Not measuredOnly Claude Sonnet 5.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index220
General benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
Vals Index70.8%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench data analysis59.5%Not measuredOnly Claude Sonnet 5.5 measured
Public Benefits Bench (Vals AI)67.2%Not measuredOnly Claude Sonnet 5.5 measured
SAGE (Vals AI)51.8%37.6%Claude Sonnet 5.5
MedScribe (Vals AI)91.1%67.7%Claude Sonnet 5.5
Vals Multimodal IndexNot measured34.8%Only Mistral Medium 3.5 measured
IFBenchNot measured68.8%Only Mistral Medium 3.5 measured
Long context reasoning (AA-LCR)82.7%69.3%Claude Sonnet 5.5
DTBench97.3%75.5%Claude Sonnet 5.5
LMCA68.3%26.1%Claude Sonnet 5.5
Surface Evolver BenchNot measured26.9%Only Mistral Medium 3.5 measured
Furniture assembly75.0%Not measuredOnly Claude Sonnet 5.5 measured
LMArena Text14731421Claude Sonnet 5.5
LMArena Text: instruction following14921415Claude Sonnet 5.5
LMArena Text: creative writing14671374Claude Sonnet 5.5
LMArena Vision12871222Claude Sonnet 5.5
LMArena Text: English14841433Claude Sonnet 5.5
LMArena Text: non-English14561404Claude Sonnet 5.5
LMArena Text: Chinese15351444Claude Sonnet 5.5
LMArena Text: GermanNot measured1453Only Mistral Medium 3.5 measured
LMArena Text: KoreanNot measured1384Only Mistral Medium 3.5 measured
LMArena Text: French14991448Claude Sonnet 5.5
LMArena Text: Spanish14511411Claude Sonnet 5.5
LMArena Text: Russian14541395Claude Sonnet 5.5
LMArena Text: PolishNot measured1430Only Mistral Medium 3.5 measured
LMArena Text: multi-turn14651423Claude Sonnet 5.5
LMArena Text: longer queries14951415Claude Sonnet 5.5
LMArena Text: writing and language14741384Claude Sonnet 5.5
LMArena Text: entertainment and media14611382Claude Sonnet 5.5
LMArena Vision: English12891240Claude Sonnet 5.5
LMArena Vision: ChineseNot measured1244Only Mistral Medium 3.5 measured
LMArena Vision: reading text12971233Claude Sonnet 5.5
LMArena Vision: humorNot measured1216Only Mistral Medium 3.5 measured
LMArena Vision: creative writing12421198Claude Sonnet 5.5
Neither model has a result on the other 12 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Sonnet 5.5 and Mistral Medium 3.5
BenchmarkClaude Sonnet 5.5Mistral Medium 3.5Leader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Claude Sonnet 5.5$0.0070Fits in one request
Mistral Medium 3.5$0.0053Fits in one request

Mistral Medium 3.5 costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 5.5$0.130Fits in one request
Mistral Medium 3.5$0.098Fits in one request

Mistral Medium 3.5 costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 5.5$0.500Fits in one request
Mistral Medium 3.5$0.375Fits in one request

Mistral Medium 3.5 costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Claude Sonnet 5.5 and Mistral Medium 3.5
SpecificationAnthropic Claude Sonnet 5.5Mistral Medium 3.5
MakerAnthropicMistral AI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 28, 2026April 30, 2026
Context window1M262K
Input $/Mtok$2.00$1.50
Output $/Mtok$10.00$7.50
Coding index88.99.2
Independent measurements behind it21
Cost per solved taskNot computable$6.02
SourceOpenRouter listingOpenRouter listing

Questions

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

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 9.2 for Mistral Medium 3.5. Pick Mistral Medium 3.5 when output tokens cost 1.3x less.

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

Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; Mistral Medium 3.5 costs $1.50 and $7.50. Cost per solved task is known for Mistral Medium 3.5 only.

Which has the bigger context window, Claude Sonnet 5.5 or Mistral Medium 3.5?

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

How many benchmarks is the Claude Sonnet 5.5 vs Mistral Medium 3.5 comparison based on?

58 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 5.5's coding index rests on 2 independent benchmarks and Mistral Medium 3.5's on 1. Where only one model has a result, the page says so instead of naming a winner.

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