Model comparison
Claude Opus 5.5 vs Magistral Small
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 30.2 on the Noometry Index. Magistral Small costs 11× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.
Last verified . 8 shared benchmarks.
Mistral AISummary
- They share 8 benchmarks with published results for both. Claude Opus 5.5 scores higher in 4 categories and Magistral Small in 0 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 5.5 leads 80.2 to 6.8.
- The biggest single-benchmark swing is ARC-AGI-1: 98.5% for Claude Opus 5.5 and 5% for Magistral Small.
- Magistral Small is cheaper at $0.50 / $1.50 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
- Claude Opus 5.5 accepts more context: 1M tokens versus 128K.
- Magistral Small has downloadable open weights; the other is API-only.
Side by side
| Claude Opus 5.5 | Magistral Small | |
|---|---|---|
| Provider | Anthropic | Mistral AI |
| Noometry Index | 68.6 | 30.2 |
| Released | 2026-09-22 | 2025-06-10 |
| Weights | Proprietary | Open |
| Context window | 1M | 128K |
| Max output | 128K | 40K |
| Input $ / M tokens | $4 | $0.50 |
| Output $ / M tokens | $20 | $1.50 |
| Results tracked | 44 | 10 |
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Category by category
Coding Claude Opus 5.5 leads
Claude Opus 5.5: 71.9 (#3), Magistral Small: 38.4 (#176)
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| SciCode | 66.9% | 35.2% |
| FrontierCode | 54.6% | — |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1813 | — |
| FrontierSWE | 62.3% | — |
| LMArena Coding | 1547 | — |
| MirrorCode | 77.4% | — |
| ALE-Bench | 2,147 | — |
Agentic & Tool Use Not comparable
Claude Opus 5.5: 45.3 (#15), Magistral Small: —
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| APEX-Agents | 73.5% | — |
| GDP.pdf | 30.6% | — |
| Vending-Bench 2 | 9,235 | — |
Reasoning Claude Opus 5.5 leads
Claude Opus 5.5: 80.2 (#3), Magistral Small: 6.8 (#350)
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| ARC-AGI-2 | 93.3% | 0% |
| ARC-AGI-1 | 98.5% | 5% |
| CritPt | 31.7% | 0.3% |
| DTBench | 98.9% | 61.3% |
| Epoch Capabilities Index | 167.33 | 133.19 |
| Kagi LLM Benchmark | — | 6.3% |
| NYT Connections (extended) | 88.5% | — |
| Chess Puzzles | — | 3% |
| EBR-Bench | 71.4% | — |
| LMArena Hard Prompts | 1535 | — |
| Mystery Game Puzzles | 71% | — |
| LMCA | 68.2% | — |
Math Claude Opus 5.5 leads
Claude Opus 5.5: 91.8 (#3), Magistral Small: 26.2 (#261)
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 30% |
| FrontierMath (Tiers 1-3) | 91.2% | — |
| FrontierMath Tier 4 | 95% | — |
| ProofBench | 100% | — |
| LMArena Math | 1506 | — |
| FrontierMath Erdős | 2.9% | — |
Knowledge Claude Opus 5.5 leads
Claude Opus 5.5: 66.4 (#10), Magistral Small: 30.9 (#223)
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| GPQA Diamond | 90.6% | 56.1% |
| SimpleQA Verified | 72.2% | — |
| LMArena Expert | 1547 | — |
Multimodal Not comparable
Claude Opus 5.5: 57.8 (#1), Magistral Small: —
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| LMArena Vision | 1321 | — |
| Blueprint-Bench 2 | 51.2% | — |
| Furniture Assembly | 83.3% | — |
Multilingual Not comparable
Claude Opus 5.5: 59.1 (#2), Magistral Small: —
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| LMArena Non-English | 1507 | — |
| LMArena Chinese | 1588 | — |
| LMArena French | 1514 | — |
| LMArena Russian | 1520 | — |
| LMArena Spanish | 1507 | — |
Instruction Following Not comparable
Claude Opus 5.5: 80.0 (#3), Magistral Small: —
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| LMArena Instruction Following | 1537 | — |
Long Context Not comparable
Claude Opus 5.5: 47.1 (#19), Magistral Small: —
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| LMArena Longer Query | 1532 | — |
Writing & Preference Not comparable
Claude Opus 5.5: 78.2 (#3), Magistral Small: —
| Benchmark | Claude Opus 5.5 | Magistral Small |
|---|---|---|
| LMArena Text | 1515 | — |
| LMArena Creative Writing | 1533 | — |
| EQ-Bench Creative Writing | 2050 | — |
| LMArena Multi-Turn | 1499 | — |
Frequently asked questions
Is Claude Opus 5.5 better than Magistral Small?
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 30.2 on the Noometry Index. Magistral Small costs 11× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 5.5 or Magistral Small?
Magistral Small is cheaper. It lists at $0.50 per million input tokens and $1.50 per million output tokens; Claude Opus 5.5 lists at $4 and $20.
Is Claude Opus 5.5 or Magistral Small better for coding?
Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 38.4 in the Noometry coding category.
Which has the bigger context window?
Claude Opus 5.5 does, with 1M tokens against 128K.
How many benchmarks do Claude Opus 5.5 and Magistral Small share?
8 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Magistral Small has 10.