Claude Sonnet 5.5 vs Mistral Small 3
Claude Sonnet 5.5 leads Mistral Small 3 on the Artificial Analysis Intelligence Index, 56.0 to 6.7, and Mistral Small 3 costs 125.0x less per output token ($0.08 vs $10.00 per million). Updated October 22, 2026; 26 benchmarks have a result for both.
vs boards won of 26 shared
Claude Sonnet 5.5 or Mistral Small 3: which to pick
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; Mistral Small 3 has none, so the two cannot be ranked on coding.
Pick Mistral Small 3 for output tokens 125.0x cheaper ($0.08 vs $10.00 per million).
Model AClaude Sonnet 5.5Anthropic87.3/1005 independent benchmarksNo cost per solved taskModel BMistral Small 3Mistral AINot benchmarkedNo coding benchmarkNo cost per solved task
- Shared results
- 26
- Claude Sonnet 5.5 only
- 70
- Mistral Small 3 only
- 10
- Like-for-like categories
- 6 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
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.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Only Claude Sonnet 5.5 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 56.0 against 6.7.
Same board, both measured
Web design
Design Arena: websites
No call
Only Claude Sonnet 5.5 has a Design Arena: websites result, 1326.
Directional only
General
Vals Index
No call
Only Claude Sonnet 5.5 has a Vals Index result, 70.8%.
Directional only
Long documents
Listed context window
Claude Sonnet 5.5
Claude Sonnet 5.5 takes 1M tokens against 33K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mistral Small 3
Claude Sonnet 5.5 $0.0070, Mistral Small 3 $0.0001 per turn.
List prices
At a glance
- Coding index
- Claude Sonnet 5.5 87.3 from 5 benchmarks, Mistral Small 3 not benchmarked.
- Widest category
- Intelligence, 49.3 points apart on average over 1 shared benchmark.
- Widest single gap
- Long context reasoning (AA-LCR): Claude Sonnet 5.5 82.7% against Mistral Small 3 0.0%, 82.7 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 5.5 $10.00 against Mistral Small 3 $0.08 per million output tokens, 125.0x apart.
- Context window
- Claude Sonnet 5.5 takes 1M tokens, Mistral Small 3 33K.
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.
| Category | Claude Sonnet 5.5 | Bars | Mistral Small 3 | Ties |
|---|---|---|---|---|
| Coding | 2 | 0 | ||
| Intelligence | 1 | 0 | ||
| Reasoning | 4 | 0 | ||
| Math | 2 | 0 | ||
| Knowledge | 4 | 0 | ||
| General | 13 | 0 | ||
| All shared boards | 26 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index20
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| LiveBench coding | 94.7% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev | 1768 | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 4 (Vals AI) | 64.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Vibe Code Bench (Vals AI) | 92.4% | Not measured | Only Claude Sonnet 5.5 measured |
| Code migration (Vals AI) | 69.8% | Not measured | Only Claude Sonnet 5.5 measured |
| ProgramBench (Vals AI) | 6.5% | Not measured | Only Claude Sonnet 5.5 measured |
| IOI (Vals AI) | 83.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 2.1 (Vals AI) | 83.2% | Not measured | Only Claude Sonnet 5.5 measured |
| SWE-bench Multimodal (Vals AI) | 58.3% | Not measured | Only Claude Sonnet 5.5 measured |
| CyberBench (Vals AI) | 59.6% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 25.2% | Only Mistral Small 3 measured |
| SciCode | 61.0% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierCode | 52.1% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierSWE | 61.9% | Not measured | Only Claude Sonnet 5.5 measured |
| ALE-Bench | 1819.1 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: coding | 1513 | 1246 | Claude Sonnet 5.5 |
| LMArena Text: software and IT | 1504 | 1248 | Claude Sonnet 5.5 |
| LMArena WebDev: React | 1817 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev: HTML | 1741 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev: from an image | 1737 | Not measured | Only Claude Sonnet 5.5 measured |
| SciCode | 13.8% | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 18 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 56.0 | 6.7 | Claude Sonnet 5.5 |
| Epoch Capabilities Index | 166.2 | Not measured | Only Claude Sonnet 5.5 measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index19 boards, none shared
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1305 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: agents building mobile apps | 1260 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: spreadsheets | 1260 | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench research | 83.6% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench browser | 84.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench long agentic | 78.8% | Not measured | Only Claude Sonnet 5.5 measured |
| SREBench (Vals AI) | 30.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Finance Agent (Vals AI) | 58.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Tax Agent Bench (Vals AI) | 42.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Legal Research Bench (Vals AI) | 48.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 10.4% | Not measured | Only Claude Sonnet 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 75.7% | Not measured | Only Claude Sonnet 5.5 measured |
| BioMysteryBench (Vals AI) | 81.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench-Science (Vals AI) | 47.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Vals Science Index | 59.1% | Not measured | Only Claude Sonnet 5.5 measured |
| τ²-Bench Telecom | Not measured | 19.6% | Only Mistral Small 3 measured |
| APEX-Agents | 75.5% | Not measured | Only Claude Sonnet 5.5 measured |
| SpireClimb | 1.3% | Not measured | Only Claude Sonnet 5.5 measured |
| Vending-Bench 2 | $11,165 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 22 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| LiveBench reasoning | 91.6% | Not measured | Only Claude Sonnet 5.5 measured |
| MysteryMechanism (Vals AI) | 49.1% | Not measured | Only Claude Sonnet 5.5 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 46.2% | Only Mistral Small 3 measured |
| Humanity's Last Exam (Artificial Analysis run) | 55.0% | 3.8% | Claude Sonnet 5.5 |
| GPQA Diamond (Epoch AI run) | 95.6% | Not measured | Only Claude Sonnet 5.5 measured |
| Chess puzzles | 59.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Mystery game puzzles | 65.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: hard prompts | 1494 | 1233 | Claude Sonnet 5.5 |
| LMArena Text: expert | 1531 | 1202 | Claude Sonnet 5.5 |
| LMArena Text: hard prompts in English | 1502 | 1243 | Claude Sonnet 5.5 |
| LMArena Vision: diagrams | 1329 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Vision: homework | 1331 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 10 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| AA Math Index | Not measured | 4.3 | Only Mistral Small 3 measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 4.3% | Only Mistral Small 3 measured |
| OTIS Mock AIME | 100.0% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierMath, tiers 1 to 3 | 88.8% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierMath, tier 4 | 80.5% | Not measured | Only Claude Sonnet 5.5 measured |
| ProofBench | 100.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: math | 1497 | 1240 | Claude Sonnet 5.5 |
| LMArena Text: mathematical work | 1510 | 1243 | Claude Sonnet 5.5 |
| Neither model has a result on the other 5 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| MedCode (Vals AI) | 52.9% | Not measured | Only Claude Sonnet 5.5 measured |
| MMLU Pro (Artificial Analysis run) | Not measured | 65.2% | Only Mistral Small 3 measured |
| SimpleQA Verified | 46.5% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: science | 1483 | 1235 | Claude Sonnet 5.5 |
| LMArena Text: medicine and healthcare | 1464 | 1215 | Claude Sonnet 5.5 |
| LMArena Text: legal and government | 1483 | 1219 | Claude Sonnet 5.5 |
| LMArena Text: business and finance | 1468 | 1205 | Claude Sonnet 5.5 |
| Neither model has a result on the other 11 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1326 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: UI components | 1368 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: game dev | 1471 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: data viz | 1392 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: 3D | 1445 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: all code categories | 1364 | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench design | 85.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 2 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index130
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| Vals Index | 70.8% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench data analysis | 59.5% | Not measured | Only Claude Sonnet 5.5 measured |
| Public Benefits Bench (Vals AI) | 67.2% | Not measured | Only Claude Sonnet 5.5 measured |
| SAGE (Vals AI) | 51.8% | Not measured | Only Claude Sonnet 5.5 measured |
| MedScribe (Vals AI) | 91.1% | Not measured | Only Claude Sonnet 5.5 measured |
| IFBench | Not measured | 26.4% | Only Mistral Small 3 measured |
| Long context reasoning (AA-LCR) | 82.7% | 0.0% | Claude Sonnet 5.5 |
| DTBench | 97.3% | Not measured | Only Claude Sonnet 5.5 measured |
| LMCA | 68.3% | Not measured | Only Claude Sonnet 5.5 measured |
| Furniture assembly | 75.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text | 1473 | 1234 | Claude Sonnet 5.5 |
| LMArena Text: instruction following | 1492 | 1214 | Claude Sonnet 5.5 |
| LMArena Text: creative writing | 1467 | 1194 | Claude Sonnet 5.5 |
| LMArena Vision | 1287 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: English | 1484 | 1256 | Claude Sonnet 5.5 |
| LMArena Text: non-English | 1456 | 1198 | Claude Sonnet 5.5 |
| LMArena Text: Chinese | 1535 | 1204 | Claude Sonnet 5.5 |
| LMArena Text: German | Not measured | 1211 | Only Mistral Small 3 measured |
| LMArena Text: Japanese | Not measured | 1111 | Only Mistral Small 3 measured |
| LMArena Text: Korean | Not measured | 1188 | Only Mistral Small 3 measured |
| LMArena Text: French | 1499 | 1204 | Claude Sonnet 5.5 |
| LMArena Text: Spanish | 1451 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: Russian | 1454 | 1216 | Claude Sonnet 5.5 |
| LMArena Text: multi-turn | 1465 | 1217 | Claude Sonnet 5.5 |
| LMArena Text: longer queries | 1495 | 1246 | Claude Sonnet 5.5 |
| LMArena Text: writing and language | 1474 | 1214 | Claude Sonnet 5.5 |
| LMArena Text: entertainment and media | 1461 | 1184 | Claude Sonnet 5.5 |
| LMArena Vision: English | 1289 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Vision: reading text | 1297 | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Vision: creative writing | 1242 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 | Leader |
|---|---|---|---|
| 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 Small 3$0.0001Fits in one request
Mistral Small 3 costs less
Repository review
50K input + 3K output tokens
Claude Sonnet 5.5$0.130Fits in one request
Mistral Small 3$0.0027Exceeds the context window
Mistral Small 3 costs less
Agent loop
200K input + 10K output tokens
Claude Sonnet 5.5$0.500Fits in one request
Mistral Small 3$0.011Exceeds the context window
Mistral Small 3 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.
| Specification | Anthropic Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| Maker | Anthropic | Mistral AI |
| Weights | No public weights listed | Open weights |
| Released | September 28, 2026 | January 30, 2025 |
| Context window | 1M | 33K |
| Input $/Mtok | $2.00 | $0.05 |
| Output $/Mtok | $10.00 | $0.08 |
| Coding index | 87.3 | Not benchmarked |
| Independent measurements behind it | 5 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 5.5 better than Mistral Small 3 for coding?
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; Mistral Small 3 has none, so the two cannot be ranked on coding. Pick Mistral Small 3 for output tokens 125.0x cheaper ($0.08 vs $10.00 per million).
Which is cheaper, Claude Sonnet 5.5 or Mistral Small 3?
Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; Mistral Small 3 costs $0.05 and $0.08. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Sonnet 5.5 or Mistral Small 3?
Claude Sonnet 5.5, with 1M tokens against 33K.
How many benchmarks is the Claude Sonnet 5.5 vs Mistral Small 3 comparison based on?
26 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 5.5's coding index rests on 5 independent benchmarks and Mistral Small 3's on 0. Where only one model has a result, the page says so instead of naming a winner.