Model comparison
GPT-5.5 Instant vs Mistral Medium 3.5
GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 39.6 on the Noometry Index.
Last verified . 18 shared benchmarks.
Mistral AISummary
- They share 18 benchmarks with published results for both. GPT-5.5 Instant scores higher in 7 categories and Mistral Medium 3.5 in 2 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in math, where Mistral Medium 3.5 leads 36.4 to 26.1.
- Mistral Medium 3.5 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.5 Instant | Mistral Medium 3.5 | |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 42.5 | 39.6 |
| Released | 2026-05-05 | — |
| Weights | Proprietary | Open |
| Context window | — | 262K |
| Max output | — | 210K |
| Input $ / M tokens | — | $1.50 |
| Output $ / M tokens | — | $7.50 |
| Results tracked | 27 | 22 |
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Category by category
Coding GPT-5.5 Instant leads
GPT-5.5 Instant: 43.7 (#73), Mistral Medium 3.5: 35.7 (#208)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Coding | 1433 | 1461 |
| LMArena WebDev | — | 1263 |
| SciCode | 48.6% | — |
Reasoning GPT-5.5 Instant leads
GPT-5.5 Instant: 24.2 (#149), Mistral Medium 3.5: 16.6 (#290)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Hard Prompts | 1426 | 1436 |
| Epoch Capabilities Index | 142.48 | 141.42 |
| Kagi LLM Benchmark | — | 41.4% |
| NYT Connections (extended) | — | 12.9% |
| CritPt | 0% | — |
| Chess Puzzles | 12% | — |
Math Mistral Medium 3.5 leads
GPT-5.5 Instant: 26.1 (#241), Mistral Medium 3.5: 36.4 (#113)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Math | 1420 | 1432 |
| FrontierMath (Tiers 1-3) | 26.3% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 68.1% | — |
Knowledge GPT-5.5 Instant leads
GPT-5.5 Instant: 48.9 (#68), Mistral Medium 3.5: 39.3 (#123)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Expert | 1409 | 1431 |
| GPQA Diamond | 82.5% | — |
Multimodal GPT-5.5 Instant leads
GPT-5.5 Instant: 39.3 (#48), Mistral Medium 3.5: 37.6 (#64)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Vision | 1250 | 1222 |
| LMArena Document | 1403 | — |
Multilingual Too close to call
GPT-5.5 Instant: 53.0 (#76), Mistral Medium 3.5: 52.1 (#93)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Non-English | 1417 | 1405 |
| LMArena Chinese | 1457 | 1443 |
| LMArena French | 1428 | 1448 |
| LMArena German | 1410 | 1453 |
| LMArena Korean | 1393 | 1387 |
| LMArena Russian | 1430 | 1396 |
| LMArena Spanish | 1430 | 1406 |
| LMArena Japanese | 1408 | — |
Instruction Following Too close to call
GPT-5.5 Instant: 74.4 (#94), Mistral Medium 3.5: 74.7 (#87)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Instruction Following | 1407 | 1414 |
Long Context Too close to call
GPT-5.5 Instant: 43.4 (#92), Mistral Medium 3.5: 43.2 (#101)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Longer Query | 1422 | 1414 |
Writing & Preference GPT-5.5 Instant leads
GPT-5.5 Instant: 62.0 (#81), Mistral Medium 3.5: 58.6 (#113)
| Benchmark | GPT-5.5 Instant | Mistral Medium 3.5 |
|---|---|---|
| LMArena Text | 1419 | 1421 |
| LMArena Creative Writing | 1420 | 1372 |
| LMArena Multi-Turn | 1434 | 1423 |
| EQ-Bench 4 | — | 993 |
Frequently asked questions
Is GPT-5.5 Instant better than Mistral Medium 3.5?
GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 39.6 on the Noometry Index.
Is GPT-5.5 Instant or Mistral Medium 3.5 better for coding?
GPT-5.5 Instant scores higher on coding benchmarks: 43.7 versus 35.7 in the Noometry coding category.
How many benchmarks do GPT-5.5 Instant and Mistral Medium 3.5 share?
18 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and Mistral Medium 3.5 has 22.