Model comparison
GPT-5.5 Pro vs Mistral Small
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 33.4 on the Noometry Index. Mistral Small costs 257× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Last verified . 5 shared benchmarks.
Mistral AISummary
- They share 5 benchmarks with published results for both. GPT-5.5 Pro scores higher in 3 categories and Mistral Small in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.5 Pro leads 84.0 to 16.4.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for GPT-5.5 Pro and 5.8% for Mistral Small.
- Mistral Small is cheaper at $0.15 / $0.60 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 262K.
- Mistral Small has downloadable open weights; the other is API-only.
Side by side
| GPT-5.5 Pro | Mistral Small | |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 64.3 | 33.4 |
| Released | 2026-04-23 | 2024-02-26 |
| Weights | Proprietary | Open |
| Context window | 1.05M | 262K |
| Max output | 128K | 256K |
| Input $ / M tokens | $30 | $0.15 |
| Output $ / M tokens | $180 | $0.60 |
| Results tracked | 14 | 39 |
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Category by category
Coding Not comparable
GPT-5.5 Pro: —, Mistral Small: 34.0 (#247)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| SciCode | — | 26.5% |
| BigCodeBench Instruct | — | 36.1% |
| LiveBench Coding | — | 36.2% |
| LMArena Coding | — | 1362 |
| BigCodeBench Complete | — | 46.6% |
| ALE-Bench | — | 497.62 |
Agentic & Tool Use Not comparable
GPT-5.5 Pro: —, Mistral Small: 28.1 (#93)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 37.1% |
Reasoning GPT-5.5 Pro leads
GPT-5.5 Pro: 73.3 (#10), Mistral Small: 19.8 (#250)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| CritPt | 30.6% | 0% |
| DTBench | 96% | 70.9% |
| LMCA | 53.9% | 20.6% |
| ARC-AGI-2 | 84.6% | — |
| SimpleBench | 76.9% | — |
| Kagi LLM Benchmark | — | 37.8% |
| ARC-AGI-1 | 96.5% | — |
| Chess Puzzles | 64% | — |
| LiveBench Reasoning | — | 44.8% |
| LMArena Hard Prompts | — | 1335 |
| LiveBench Data Analysis | — | 53.7% |
| Epoch Capabilities Index | 162.07 | — |
| LiveBench | — | 44% |
Math GPT-5.5 Pro leads
GPT-5.5 Pro: 84.0 (#10), Mistral Small: 16.4 (#293)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 5.8% |
| FrontierMath (Tiers 1-3) | 87.7% | — |
| FrontierMath Tier 4 | 78% | — |
| LiveBench Math | — | 39.9% |
| LMArena Math | — | 1341 |
| MATH Level 5 | — | 46.8% |
| FrontierMath (Feb 2025 set) | 52.4% | — |
| FrontierMath Tier 4 (v1) | 39.6% | — |
Knowledge GPT-5.5 Pro leads
GPT-5.5 Pro: 64.1 (#19), Mistral Small: 31.0 (#222)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| GPQA Diamond | 93.9% | 47.5% |
| Vectara Hallucination Rate | — | 5.1% |
| LMArena Expert | — | 1291 |
| MMLU | — | 68.7% |
Multimodal Not comparable
GPT-5.5 Pro: —, Mistral Small: 33.5 (#96)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| LMArena Vision | — | 1142 |
Multilingual Not comparable
GPT-5.5 Pro: —, Mistral Small: 45.5 (#169)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| LMArena Non-English | — | 1315 |
| LMArena Chinese | — | 1340 |
| LMArena French | — | 1337 |
| LMArena German | — | 1340 |
| LMArena Japanese | — | 1275 |
| LMArena Korean | — | 1259 |
| LMArena Russian | — | 1324 |
| LMArena Spanish | — | 1346 |
Instruction Following Not comparable
GPT-5.5 Pro: —, Mistral Small: 66.4 (#209)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| LiveBench Instruction Following | — | 63.7% |
| LMArena Instruction Following | — | 1310 |
Long Context Not comparable
GPT-5.5 Pro: —, Mistral Small: 40.4 (#156)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| LMArena Longer Query | — | 1327 |
Writing & Preference Not comparable
GPT-5.5 Pro: —, Mistral Small: 52.5 (#171)
| Benchmark | GPT-5.5 Pro | Mistral Small |
|---|---|---|
| LMArena Text | — | 1338 |
| LMArena Creative Writing | — | 1305 |
| LMArena Multi-Turn | — | 1344 |
| LiveBench Language | — | 30.5% |
Frequently asked questions
Is GPT-5.5 Pro better than Mistral Small?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 33.4 on the Noometry Index. Mistral Small costs 257× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Which is cheaper, GPT-5.5 Pro or Mistral Small?
Mistral Small is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; GPT-5.5 Pro lists at $30 and $180.
Which has the bigger context window?
GPT-5.5 Pro does, with 1.05M tokens against 262K.
How many benchmarks do GPT-5.5 Pro and Mistral Small share?
5 benchmarks have published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and Mistral Small has 39.