Model comparison
Claude Opus 5 vs Mistral Small 3.1
Claude Opus 5 is the stronger model overall, scoring 67.8 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 25× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Last verified . 23 shared benchmarks.
Mistral AISummary
- They share 23 benchmarks with published results for both. Claude Opus 5 scores higher in 9 categories and Mistral Small 3.1 in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5 leads 86.2 to 14.7.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 98.9% for Claude Opus 5 and 3.9% for Mistral Small 3.1.
- Mistral Small 3.1 is cheaper at $0.35 / $0.56 per million input/output tokens, against $5 / $25 for Claude Opus 5.
- Claude Opus 5 accepts more context: 1M tokens versus 128K.
- Mistral Small 3.1 has downloadable open weights; the other is API-only.
Side by side
| Claude Opus 5 | Mistral Small 3.1 | |
|---|---|---|
| Provider | Anthropic | Mistral AI |
| Noometry Index | 67.8 | 31.7 |
| Released | 2026-07-24 | 2025-03-17 |
| Weights | Proprietary | Open |
| Context window | 1M | 128K |
| Max output | 128K | 102K |
| Input $ / M tokens | $5 | $0.35 |
| Output $ / M tokens | $25 | $0.56 |
| Results tracked | 57 | 28 |
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Category by category
Coding Claude Opus 5 leads
Claude Opus 5: 67.5 (#5), Mistral Small 3.1: 38.3 (#179)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Coding | 1534 | 1309 |
| DeepSWE | 73.6% | — |
| FrontierCode | 53.4% | — |
| CursorBench | 46.6% | — |
| LMArena WebDev | 1691 | — |
| FrontierSWE | 52% | — |
| SciCode | 56.4% | — |
| WeirdML | 91.8% | — |
| ALE-Bench | 2,165 | — |
Agentic & Tool Use Not comparable
Claude Opus 5: 55.6 (#1), Mistral Small 3.1: —
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| APEX-Agents | 65.8% | — |
| OSWorld 2.0 | 31.4% | — |
| τ²-bench Banking | 48.7% | — |
| PostTrainBench | 35% | — |
| BALROG | 63.4% | — |
| GBAEval | 79.6% | — |
| GDP.pdf | 24% | — |
| Vending-Bench 2 | 11,182 | — |
Reasoning Claude Opus 5 leads
Claude Opus 5: 77.2 (#4), Mistral Small 3.1: 19.7 (#254)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| Chess Puzzles | 42% | 1% |
| LMArena Hard Prompts | 1526 | 1278 |
| Epoch Capabilities Index | 162.78 | 127.48 |
| ARC-AGI-2 | 90.4% | — |
| SimpleBench | 80.6% | — |
| NYT Connections (extended) | 94.3% | — |
| ARC-AGI-1 | 97.5% | — |
| CritPt | 29.1% | — |
| EBR-Bench | 45.7% | — |
| Mystery Game Puzzles | 59% | — |
| DTBench | 97.9% | — |
| LMCA | 64.5% | — |
| Bench to the Future 3 | 0.12 | — |
Math Claude Opus 5 leads
Claude Opus 5: 86.2 (#8), Mistral Small 3.1: 14.7 (#301)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 98.9% | 3.9% |
| LMArena Math | 1531 | 1262 |
| FrontierMath (Tiers 1-3) | 85.6% | — |
| FrontierMath Tier 4 | 73.2% | — |
| ProofBench | 99% | — |
| Omni-MATH | — | 24.8% |
Knowledge Claude Opus 5 leads
Claude Opus 5: 66.8 (#9), Mistral Small 3.1: 22.6 (#271)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| GPQA Diamond | 93.9% | 41.9% |
| LMArena Expert | 1557 | 1257 |
| SimpleQA Verified | 59.9% | — |
| MMLU-Pro | — | 61% |
| GPQA (HELM) | — | 39.2% |
Multimodal Claude Opus 5 leads
Claude Opus 5: 50.8 (#8), Mistral Small 3.1: 33.2 (#99)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Vision | 1319 | 1136 |
| Blueprint-Bench 2 | 30.4% | — |
| Furniture Assembly | 60.8% | — |
| LMArena Document | 1516 | — |
Multilingual Claude Opus 5 leads
Claude Opus 5: 58.8 (#4), Mistral Small 3.1: 41.2 (#209)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Non-English | 1501 | 1255 |
| LMArena Chinese | 1574 | 1253 |
| LMArena French | 1519 | 1273 |
| LMArena German | 1524 | 1266 |
| LMArena Japanese | 1516 | 1208 |
| LMArena Korean | 1521 | 1206 |
| LMArena Russian | 1507 | 1263 |
| LMArena Spanish | 1519 | 1283 |
Instruction Following Claude Opus 5 leads
Claude Opus 5: 79.2 (#7), Mistral Small 3.1: 63.6 (#230)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Instruction Following | 1517 | 1264 |
| IFEval | — | 75% |
Long Context Claude Opus 5 leads
Claude Opus 5: 46.5 (#21), Mistral Small 3.1: 39.5 (#178)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Longer Query | 1515 | 1299 |
Writing & Preference Claude Opus 5 leads
Claude Opus 5: 79.2 (#1), Mistral Small 3.1: 37.0 (#259)
| Benchmark | Claude Opus 5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Text | 1507 | 1277 |
| LMArena Creative Writing | 1491 | 1253 |
| EQ-Bench Creative Writing | 2133 | 761 |
| LMArena Multi-Turn | 1499 | 1270 |
| WildBench | — | 78.8% |
| EQ-Bench 4 | 1385 | — |
Frequently asked questions
Is Claude Opus 5 better than Mistral Small 3.1?
Claude Opus 5 is the stronger model overall, scoring 67.8 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 25× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 5 or Mistral Small 3.1?
Mistral Small 3.1 is cheaper. It lists at $0.35 per million input tokens and $0.56 per million output tokens; Claude Opus 5 lists at $5 and $25.
Is Claude Opus 5 or Mistral Small 3.1 better for coding?
Claude Opus 5 scores higher on coding benchmarks: 67.5 versus 38.3 in the Noometry coding category.
Which has the bigger context window?
Claude Opus 5 does, with 1M tokens against 128K.
How many benchmarks do Claude Opus 5 and Mistral Small 3.1 share?
23 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and Mistral Small 3.1 has 28.