Model comparison
Claude Sonnet 5.5 vs Mistral Small
Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 33.1 on the Noometry Index. Mistral Small costs 15× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.
Last verified . 5 shared benchmarks.
Mistral AISummary
- They share 5 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 6 categories and Mistral Small in 0 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 88.7 to 15.4.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for Claude Sonnet 5.5 and 5.8% for Mistral Small.
- Mistral Small is cheaper at $0.15 / $0.60 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 256K.
- Mistral Small has downloadable open weights; the other is API-only.
Side by side
| Claude Sonnet 5.5 | Mistral Small | |
|---|---|---|
| Provider | Anthropic | Mistral AI |
| Noometry Index | 60.5 | 33.1 |
| Released | 2026-09-28 | 2024-02-26 |
| Weights | Proprietary | Open |
| Context window | 1M | 256K |
| Max output | 128K | 256K |
| Input $ / M tokens | $2 | $0.15 |
| Output $ / M tokens | $10 | $0.60 |
| Results tracked | 16 | 39 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 65.5 (#6), Mistral Small: 33.5 (#242)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| SciCode | 61% | 26.5% |
| ALE-Bench | 1,819 | 497.62 |
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| LMArena WebDev | 1699 | — |
| FrontierSWE | 61.9% | — |
| BigCodeBench Instruct | — | 36.1% |
| LiveBench Coding | — | 36.2% |
| LMArena Coding | — | 1363 |
| BigCodeBench Complete | — | 46.6% |
Agentic & Tool Use Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 44.9 (#14), Mistral Small: 27.9 (#87)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| APEX-Agents | 75.5% | — |
| Berkeley Function Calling Leaderboard | — | 37.1% |
Reasoning Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 52.4 (#29), Mistral Small: 19.3 (#238)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| CritPt | 31.4% | 0% |
| Kagi LLM Benchmark | — | 37.8% |
| LiveBench Reasoning | — | 44.8% |
| LMArena Hard Prompts | — | 1336 |
| Mystery Game Puzzles | 65% | — |
| DTBench | — | 70.9% |
| LiveBench Data Analysis | — | 53.7% |
| LMCA | — | 20.6% |
| LiveBench | — | 44% |
Math Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 88.7 (#4), Mistral Small: 15.4 (#287)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 5.8% |
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| ProofBench | 100% | — |
| LiveBench Math | — | 39.9% |
| LMArena Math | — | 1341 |
| MATH Level 5 | — | 46.8% |
Knowledge Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#11), Mistral Small: 30.9 (#214)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| GPQA Diamond | 95.6% | 47.5% |
| SimpleQA Verified | 46.5% | — |
| Vectara Hallucination Rate | — | 5.1% |
| LMArena Expert | — | 1293 |
| MMLU | — | 68.7% |
Multimodal Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 53.2 (#5), Mistral Small: 32.9 (#91)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| LMArena Vision | — | 1142 |
| Furniture Assembly | 75% | — |
Multilingual Not comparable
Claude Sonnet 5.5: —, Mistral Small: 45.7 (#164)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| LMArena Non-English | — | 1315 |
| LMArena Chinese | — | 1342 |
| LMArena French | — | 1337 |
| LMArena German | — | 1341 |
| LMArena Japanese | — | 1275 |
| LMArena Korean | — | 1260 |
| LMArena Russian | — | 1324 |
| LMArena Spanish | — | 1346 |
Instruction Following Not comparable
Claude Sonnet 5.5: —, Mistral Small: 66.6 (#204)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| LiveBench Instruction Following | — | 63.7% |
| LMArena Instruction Following | — | 1310 |
Long Context Not comparable
Claude Sonnet 5.5: —, Mistral Small: 40.4 (#151)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| LMArena Longer Query | — | 1327 |
Writing & Preference Not comparable
Claude Sonnet 5.5: —, Mistral Small: 52.6 (#165)
| Benchmark | Claude Sonnet 5.5 | Mistral Small |
|---|---|---|
| LMArena Text | — | 1338 |
| LMArena Creative Writing | — | 1304 |
| LMArena Multi-Turn | — | 1344 |
| LiveBench Language | — | 30.5% |
Frequently asked questions
Is Claude Sonnet 5.5 better than Mistral Small?
Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 33.1 on the Noometry Index. Mistral Small costs 15× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.
Which is cheaper, Claude Sonnet 5.5 or Mistral Small?
Mistral Small is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.
Is Claude Sonnet 5.5 or Mistral Small better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 65.5 versus 33.5 in the Noometry coding category.
Which has the bigger context window?
Claude Sonnet 5.5 does, with 1M tokens against 256K.
How many benchmarks do Claude Sonnet 5.5 and Mistral Small share?
5 benchmarks have published results for both models. Claude Sonnet 5.5 has 16 scored results on Noometry and Mistral Small has 39.