Model comparison
GPT-6 Astra vs Mistral Small 3.1
GPT-6 Astra is the stronger model overall, scoring 70.3 to 31.4 on the Noometry Index. Mistral Small 3.1 costs 50× less per token, which makes it the better buy when GPT-6 Astra's lead doesn't matter for your workload.
Last verified . 20 shared benchmarks.
Mistral AISummary
- They share 20 benchmarks with published results for both. GPT-6 Astra 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 GPT-6 Astra leads 93.4 to 13.7.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for GPT-6 Astra 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 $10 / $50 for GPT-6 Astra.
- GPT-6 Astra accepts more context: 1.05M tokens versus 128K.
- Mistral Small 3.1 has downloadable open weights; the other is API-only.
Side by side
| GPT-6 Astra | Mistral Small 3.1 | |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 70.3 | 31.4 |
| Released | 2026-09-03 | 2025-03-17 |
| Weights | Proprietary | Open |
| Context window | 1.05M | 128K |
| Max output | 128K | 102K |
| Input $ / M tokens | $10 | $0.35 |
| Output $ / M tokens | $50 | $0.56 |
| Results tracked | 51 | 28 |
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Category by category
Coding GPT-6 Astra leads
GPT-6 Astra: 70.5 (#3), Mistral Small 3.1: 37.7 (#175)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| LMArena Coding | 1488 | 1309 |
| DeepSWE | 74.1% | — |
| FrontierCode | 53.3% | — |
| LMArena WebDev | 1792 | — |
| FrontierSWE | 65.5% | — |
| SciCode | 56.5% | — |
| WeirdML | 93.6% | — |
| MirrorCode | 46.7% | — |
| ALE-Bench | 2,951 | — |
Agentic & Tool Use Not comparable
GPT-6 Astra: 52.3 (#3), Mistral Small 3.1: —
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| APEX-Agents | 64.7% | — |
| Remote Labor Index | 20.8% | — |
| BALROG | 68.3% | — |
| Vending-Bench 2 | 15,515 | — |
Reasoning GPT-6 Astra leads
GPT-6 Astra: 85.1 (#1), Mistral Small 3.1: 18.9 (#249)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| Chess Puzzles | 72% | 1% |
| LMArena Hard Prompts | 1464 | 1278 |
| Epoch Capabilities Index | 166.6 | 127.48 |
| ARC-AGI-2 | 95% | — |
| NYT Connections (extended) | 98.1% | — |
| ARC-AGI-1 | 98.5% | — |
| CritPt | 31.7% | — |
| EBR-Bench | 76.2% | — |
| Mystery Game Puzzles | 84% | — |
| DTBench | 97.3% | — |
| LMCA | 64.4% | — |
| Bench to the Future 3 | 0.14 | — |
Math GPT-6 Astra leads
GPT-6 Astra: 93.4 (#1), Mistral Small 3.1: 13.7 (#295)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 3.9% |
| LMArena Math | 1463 | 1261 |
| FrontierMath (Tiers 1-3) | 93.7% | — |
| FrontierMath Tier 4 | 97.6% | — |
| ProofBench | 99% | — |
| Omni-MATH | — | 24.8% |
| FrontierMath Erdős | 2.9% | — |
Knowledge GPT-6 Astra leads
GPT-6 Astra: 75.3 (#1), Mistral Small 3.1: 22.6 (#266)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| GPQA Diamond | 95.8% | 41.9% |
| LMArena Expert | 1486 | 1258 |
| Humanity's Last Exam | 54.8% | — |
| SimpleQA Verified | 75.6% | — |
| MMLU-Pro | — | 61% |
| Vectara Hallucination Rate | 8.7% | — |
| GPQA (HELM) | — | 39.2% |
Multimodal GPT-6 Astra leads
GPT-6 Astra: 55.1 (#3), Mistral Small 3.1: 32.6 (#93)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| LMArena Vision | 1280 | 1136 |
| Blueprint-Bench 2 | 49.7% | — |
| Furniture Assembly | 80% | — |
| LMArena Document | 1468 | — |
Multilingual GPT-6 Astra leads
GPT-6 Astra: 54.0 (#53), Mistral Small 3.1: 41.4 (#204)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| LMArena Non-English | 1431 | 1255 |
| LMArena Chinese | 1495 | 1254 |
| LMArena French | 1467 | 1270 |
| LMArena Russian | 1434 | 1263 |
| LMArena Spanish | 1412 | 1283 |
| LMArena German | — | 1266 |
| LMArena Japanese | — | 1210 |
| LMArena Korean | — | 1206 |
Instruction Following GPT-6 Astra leads
GPT-6 Astra: 76.6 (#37), Mistral Small 3.1: 63.8 (#225)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| LMArena Instruction Following | 1454 | 1264 |
| IFEval | — | 75% |
Long Context GPT-6 Astra leads
GPT-6 Astra: 44.7 (#57), Mistral Small 3.1: 39.5 (#172)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| LMArena Longer Query | 1460 | 1300 |
Writing & Preference GPT-6 Astra leads
GPT-6 Astra: 75.7 (#7), Mistral Small 3.1: 37.2 (#254)
| Benchmark | GPT-6 Astra | Mistral Small 3.1 |
|---|---|---|
| LMArena Text | 1443 | 1278 |
| LMArena Creative Writing | 1423 | 1253 |
| EQ-Bench Creative Writing | 2173 | 761 |
| LMArena Multi-Turn | 1457 | 1270 |
| WildBench | — | 78.8% |
Frequently asked questions
Is GPT-6 Astra better than Mistral Small 3.1?
GPT-6 Astra is the stronger model overall, scoring 70.3 to 31.4 on the Noometry Index. Mistral Small 3.1 costs 50× less per token, which makes it the better buy when GPT-6 Astra's lead doesn't matter for your workload.
Which is cheaper, GPT-6 Astra 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; GPT-6 Astra lists at $10 and $50.
Is GPT-6 Astra or Mistral Small 3.1 better for coding?
GPT-6 Astra scores higher on coding benchmarks: 70.5 versus 37.7 in the Noometry coding category.
Which has the bigger context window?
GPT-6 Astra does, with 1.05M tokens against 128K.
How many benchmarks do GPT-6 Astra and Mistral Small 3.1 share?
20 benchmarks have published results for both models. GPT-6 Astra has 51 scored results on Noometry and Mistral Small 3.1 has 28.