Model comparison
Mistral Small 3.1 vs o3-pro
o3-pro is the stronger model overall, scoring 42.9 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 87× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Last verified . 1 shared benchmarks.
Mistral AISummary
- They share 1 benchmark with published results for both. Mistral Small 3.1 scores higher in 0 categories and o3-pro in 5 categories; 5 gaps are clear of the uncertainty.
- The widest gap is in long context, where o3-pro leads 72.2 to 39.5.
- Mistral Small 3.1 is cheaper at $0.35 / $0.56 per million input/output tokens, against $20 / $80 for o3-pro.
- o3-pro accepts more context: 200K tokens versus 128K.
- Mistral Small 3.1 has downloadable open weights; the other is API-only.
Side by side
| Mistral Small 3.1 | o3-pro | |
|---|---|---|
| Provider | Mistral AI | OpenAI |
| Noometry Index | 31.7 | 42.9 |
| Released | 2025-03-17 | 2025-06-10 |
| Weights | Open | Proprietary |
| Context window | 128K | 200K |
| Max output | 102K | 100K |
| Input $ / M tokens | $0.35 | $20 |
| Output $ / M tokens | $0.56 | $80 |
| Results tracked | 28 | 12 |
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Category by category
Coding o3-pro leads
Mistral Small 3.1: 38.3 (#179), o3-pro: 55.5 (#24)
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| Aider Polyglot | — | 84.9% |
| WeirdML | — | 58.2% |
| LMArena Coding | 1309 | — |
Reasoning o3-pro leads
Mistral Small 3.1: 19.7 (#254), o3-pro: 23.8 (#171)
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| Epoch Capabilities Index | 127.48 | 147.42 |
| ARC-AGI-2 | — | 4.9% |
| Kagi LLM Benchmark | — | 72.1% |
| ARC-AGI-1 | — | 59.3% |
| Chess Puzzles | 1% | — |
| LMArena Hard Prompts | 1278 | — |
| DTBench | — | 86.9% |
| LMCA | — | 38.5% |
Math Not comparable
Mistral Small 3.1: 14.7 (#301), o3-pro: —
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 3.9% | — |
| Omni-MATH | 24.8% | — |
| LMArena Math | 1262 | — |
Knowledge o3-pro leads
Mistral Small 3.1: 22.6 (#271), o3-pro: 29.5 (#238)
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| GPQA Diamond | 41.9% | — |
| MMLU-Pro | 61% | — |
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 23.3% |
| GPQA (HELM) | 39.2% | — |
| LMArena Expert | 1257 | — |
Multimodal Not comparable
Mistral Small 3.1: 33.2 (#99), o3-pro: —
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| LMArena Vision | 1136 | — |
Multilingual Not comparable
Mistral Small 3.1: 41.2 (#209), o3-pro: —
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| LMArena Non-English | 1255 | — |
| LMArena Chinese | 1253 | — |
| LMArena French | 1273 | — |
| LMArena German | 1266 | — |
| LMArena Japanese | 1208 | — |
| LMArena Korean | 1206 | — |
| LMArena Russian | 1263 | — |
| LMArena Spanish | 1283 | — |
Instruction Following Not comparable
Mistral Small 3.1: 63.6 (#230), o3-pro: —
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| IFEval | 75% | — |
| LMArena Instruction Following | 1264 | — |
Long Context o3-pro leads
Mistral Small 3.1: 39.5 (#178), o3-pro: 72.2 (#1)
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
| LMArena Longer Query | 1299 | — |
Writing & Preference o3-pro leads
Mistral Small 3.1: 37.0 (#259), o3-pro: 57.1 (#133)
| Benchmark | Mistral Small 3.1 | o3-pro |
|---|---|---|
| LMArena Text | 1277 | — |
| LMArena Creative Writing | 1253 | — |
| Short-Story Creative Writing | — | 84.4% |
| EQ-Bench Creative Writing | 761 | — |
| WildBench | 78.8% | — |
| LMArena Multi-Turn | 1270 | — |
Frequently asked questions
Is Mistral Small 3.1 better than o3-pro?
o3-pro is the stronger model overall, scoring 42.9 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 87× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Which is cheaper, Mistral Small 3.1 or o3-pro?
Mistral Small 3.1 is cheaper. It lists at $0.35 per million input tokens and $0.56 per million output tokens; o3-pro lists at $20 and $80.
Is Mistral Small 3.1 or o3-pro better for coding?
o3-pro scores higher on coding benchmarks: 55.5 versus 38.3 in the Noometry coding category.
Which has the bigger context window?
o3-pro does, with 200K tokens against 128K.
How many benchmarks do Mistral Small 3.1 and o3-pro share?
1 benchmark has published results for both models. Mistral Small 3.1 has 28 scored results on Noometry and o3-pro has 12.