GPT-6 Astra vs Mistral Medium 3.5
GPT-6 Astra leads Mistral Medium 3.5 on coding, 85.1 to 25.5 on the Vibe Coding Index, and Mistral Medium 3.5 costs 6.7x less per output token ($7.50 vs $50.00 per million). Updated October 22, 2026; 67 benchmarks have a result for both.
GPT-6 Astra or Mistral Medium 3.5: which to pick
Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5.
Pick Mistral Medium 3.5 for output tokens 6.7x cheaper ($7.50 vs $50.00 per million) and work measured by LMArena Text: French or LMArena Text: Polish, where it leads.
- Shared results
- 67
- GPT-6 Astra only
- 62
- Mistral Medium 3.5 only
- 15
- Like-for-like categories
- 8 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
GPT-6 Astra
GPT-6 Astra scores 85.1 against 25.5.
5 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
GPT-6 Astra
GPT-6 Astra leads, 52.7 against 14.2.
Same board, both measured
Agentic work
AA Agentic Index
GPT-6 Astra
GPT-6 Astra leads, 51.0 against 7.0.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Mistral Medium 3.5 has a GPQA Diamond result, 34.9%.
Directional only
Knowledge
MMLU Pro
No call
Only Mistral Medium 3.5 has a MMLU Pro result, 75.3%.
Directional only
Web design
Design Arena: websites
GPT-6 Astra
GPT-6 Astra leads, 1336 against 1142.
Same board, both measured
General
Vals Index
No call
Only GPT-6 Astra has a Vals Index result, 65.0%.
Directional only
Long documents
Listed context window
GPT-6 Astra
GPT-6 Astra takes 1.05M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mistral Medium 3.5
GPT-6 Astra $0.035, Mistral Medium 3.5 $0.0053 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Mistral Medium 3.5 has the number, $6.02.
Directional only
At a glance
- Coding index
- GPT-6 Astra 85.1 from 5 benchmarks, Mistral Medium 3.5 25.5 from 3 benchmarks.
- Widest category
- Coding, 45.8 points apart on average over 11 shared benchmarks.
- Widest single gap
- ProofBench: GPT-6 Astra 99.0% against Mistral Medium 3.5 9.0%, 90.0 points apart on a 0 to 100 scale.
- Output price
- GPT-6 Astra $50.00 against Mistral Medium 3.5 $7.50 per million output tokens, 6.7x apart.
- Context window
- GPT-6 Astra takes 1.05M tokens, Mistral Medium 3.5 262K.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | GPT-6 Astra | Bars | Mistral Medium 3.5 | Ties |
|---|---|---|---|---|
| Coding | 11 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 5 | 0 | ||
| Reasoning | 7 | 0 | ||
| Math | 3 | 0 | ||
| Knowledge | 5 | 0 | ||
| Web design | 8 | 0 | ||
| General | 24 | 2 | ||
| All shared boards | 65 | 2 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index110
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| LiveBench coding | 93.7% | Not measured | Only GPT-6 Astra measured |
| LMArena WebDev | 1774 | 1264 | GPT-6 Astra |
| AA Coding Index | 76.9 | 46.9 | GPT-6 Astra |
| SWE-bench Verified (Vals AI) | Not measured | 66.4% | Only Mistral Medium 3.5 measured |
| Terminal-Bench 4 (Vals AI) | 59.6% | Not measured | Only GPT-6 Astra measured |
| Vibe Code Bench (Vals AI) | 89.6% | 2.9% | GPT-6 Astra |
| Code migration (Vals AI) | 67.7% | 5.1% | GPT-6 Astra |
| ProgramBench (Vals AI) | 5.5% | Not measured | Only GPT-6 Astra measured |
| IOI (Vals AI) | 100.0% | Not measured | Only GPT-6 Astra measured |
| Terminal-Bench 2.1 (Vals AI) | 87.3% | 39.0% | GPT-6 Astra |
| SWE-bench Multimodal (Vals AI) | 43.3% | Not measured | Only GPT-6 Astra measured |
| Vibe Code Bench 1-100 (Vals AI) | 27.6% | Not measured | Only GPT-6 Astra measured |
| CyberBench (Vals AI) | 41.1% | Not measured | Only GPT-6 Astra measured |
| SciCode | 56.5% | 40.2% | GPT-6 Astra |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 33.3% | Only Mistral Medium 3.5 measured |
| FrontierCode | 53.3% | Not measured | Only GPT-6 Astra measured |
| FrontierSWE | 65.5% | Not measured | Only GPT-6 Astra measured |
| GSO-Bench | 79.4% | Not measured | Only GPT-6 Astra measured |
| WeirdML | 93.3% | Not measured | Only GPT-6 Astra measured |
| MirrorCode | 46.7% | Not measured | Only GPT-6 Astra measured |
| ALE-Bench | 2951.3 | 764.0 | GPT-6 Astra |
| LMArena Text: coding | 1489 | 1460 | GPT-6 Astra |
| LMArena Text: software and IT | 1474 | 1458 | GPT-6 Astra |
| LMArena WebDev: React | 1798 | 1254 | GPT-6 Astra |
| LMArena WebDev: HTML | 1775 | 1308 | GPT-6 Astra |
| LMArena WebDev: from an image | 1726 | Not measured | Only GPT-6 Astra measured |
| SciCode | 12.3% | Not measured | Only GPT-6 Astra measured |
| SWE-Bench Pro V2 | 96.9% | Not measured | Only GPT-6 Astra measured |
| SWE Atlas: Codebase QnA | 59.1% | Not measured | Only GPT-6 Astra measured |
| SWE Atlas: Refactoring | 59.1% | Not measured | Only GPT-6 Astra measured |
| SWE Atlas: Test Writing | 50.7% | Not measured | Only GPT-6 Astra measured |
| Neither model has a result on the other 12 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 52.7 | 14.2 | GPT-6 Astra |
| Epoch Capabilities Index | 168.8 | 141.4 | GPT-6 Astra |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| AA Agentic Index | 51.0 | 7.0 | GPT-6 Astra |
| Design Arena: agents building web apps | 1374 | Not measured | Only GPT-6 Astra measured |
| Design Arena: agents building full-stack apps | 1357 | Not measured | Only GPT-6 Astra measured |
| Design Arena: agents building mobile apps | 1312 | Not measured | Only GPT-6 Astra measured |
| Design Arena: agents building Godot games | 1348 | Not measured | Only GPT-6 Astra measured |
| Design Arena: PowerPoint slides | 1217 | Not measured | Only GPT-6 Astra measured |
| Design Arena: spreadsheets | 1378 | Not measured | Only GPT-6 Astra measured |
| LiveBench research | 85.2% | Not measured | Only GPT-6 Astra measured |
| LiveBench browser | 84.0% | Not measured | Only GPT-6 Astra measured |
| LiveBench long agentic | 82.4% | Not measured | Only GPT-6 Astra measured |
| SREBench (Vals AI) | 56.9% | Not measured | Only GPT-6 Astra measured |
| Finance Agent (Vals AI) | 53.5% | 32.1% | GPT-6 Astra |
| Tax Agent Bench (Vals AI) | 20.7% | 4.5% | GPT-6 Astra |
| Legal Research Bench (Vals AI) | 39.4% | 9.1% | GPT-6 Astra |
| Harvey's Legal Agent Benchmark (Vals AI) | 7.1% | Not measured | Only GPT-6 Astra measured |
| Excel Modeling Benchmark (Vals AI) | 71.7% | 11.2% | GPT-6 Astra |
| BioMysteryBench (Vals AI) | 79.3% | Not measured | Only GPT-6 Astra measured |
| Terminal-Bench-Science (Vals AI) | 62.9% | Not measured | Only GPT-6 Astra measured |
| Vals Science Index | 65.1% | Not measured | Only GPT-6 Astra measured |
| Time Horizon Index (Vals AI) | 90.5% | Not measured | Only GPT-6 Astra measured |
| CUA-bench (Vals AI) | 19.2% | Not measured | Only GPT-6 Astra measured |
| Robo-bench (Vals AI) | 23.3% | Not measured | Only GPT-6 Astra measured |
| τ²-Bench Telecom | Not measured | 94.2% | Only Mistral Medium 3.5 measured |
| APEX-Agents | 64.7% | Not measured | Only GPT-6 Astra measured |
| Remote Labor Index | 20.8% | Not measured | Only GPT-6 Astra measured |
| BALROG | 68.3% | Not measured | Only GPT-6 Astra measured |
| SpireClimb | 25.7% | Not measured | Only GPT-6 Astra measured |
| Vending-Bench 2 | $15,515 | Not measured | Only GPT-6 Astra measured |
| Neither model has a result on the other 14 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index70
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 34.9% | Only Mistral Medium 3.5 measured |
| LiveBench reasoning | 92.7% | Not measured | Only GPT-6 Astra measured |
| MysteryMechanism (Vals AI) | 53.1% | Not measured | Only GPT-6 Astra measured |
| GPQA Diamond (Artificial Analysis run) | 96.3% | 74.8% | GPT-6 Astra |
| Humanity's Last Exam (Artificial Analysis run) | 54.7% | 13.8% | GPT-6 Astra |
| GPQA Diamond (Epoch AI run) | 95.8% | Not measured | Only GPT-6 Astra measured |
| ARC-AGI | 98.5% | Not measured | Only GPT-6 Astra measured |
| ARC-AGI-2 | 95.0% | Not measured | Only GPT-6 Astra measured |
| Chess puzzles | 74.0% | Not measured | Only GPT-6 Astra measured |
| Mystery game puzzles | 84.0% | Not measured | Only GPT-6 Astra measured |
| EBR-bench | 76.2% | Not measured | Only GPT-6 Astra measured |
| LMArena Text: hard prompts | 1463 | 1436 | GPT-6 Astra |
| LMArena Text: expert | 1489 | 1432 | GPT-6 Astra |
| LMArena Text: hard prompts in English | 1464 | 1445 | GPT-6 Astra |
| LMArena Vision: diagrams | 1297 | 1254 | GPT-6 Astra |
| LMArena Vision: homework | 1337 | 1230 | GPT-6 Astra |
| Kagi LLM Benchmark | Not measured | 41.4% | Only Mistral Medium 3.5 measured |
| Humanity's Last Exam (Scale run) | 60.6% | Not measured | Only GPT-6 Astra measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | Not measured | Only GPT-6 Astra measured |
| FrontierMath, tiers 1 to 3 | 93.7% | Not measured | Only GPT-6 Astra measured |
| FrontierMath, tier 4 | 97.6% | Not measured | Only GPT-6 Astra measured |
| ProofBench | 99.0% | 9.0% | GPT-6 Astra |
| LMArena Text: math | 1465 | 1431 | GPT-6 Astra |
| LMArena Text: mathematical work | 1484 | 1440 | GPT-6 Astra |
| MathArena | 81.9% | Not measured | Only GPT-6 Astra measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 75.3% | Only Mistral Medium 3.5 measured |
| CaseLaw (Vals AI) | Not measured | 44.2% | Only Mistral Medium 3.5 measured |
| CorpFin (Vals AI) | Not measured | 58.8% | Only Mistral Medium 3.5 measured |
| TaxEval (Vals AI) | Not measured | 68.0% | Only Mistral Medium 3.5 measured |
| MortgageTax (Vals AI) | Not measured | 28.9% | Only Mistral Medium 3.5 measured |
| MedCode (Vals AI) | 48.5% | 33.8% | GPT-6 Astra |
| SimpleQA Verified | 75.6% | Not measured | Only GPT-6 Astra measured |
| LMArena Text: science | 1451 | 1428 | GPT-6 Astra |
| LMArena Text: medicine and healthcare | 1425 | 1409 | GPT-6 Astra |
| LMArena Text: legal and government | 1462 | 1437 | GPT-6 Astra |
| LMArena Text: business and finance | 1439 | 1426 | GPT-6 Astra |
| FACTS Benchmark Suite | 75.7% | Not measured | Only GPT-6 Astra measured |
| PRBench Finance | 47.5% | Not measured | Only GPT-6 Astra measured |
| PRBench Legal | 48.4% | Not measured | Only GPT-6 Astra measured |
| Neither model has a result on the other 6 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index80
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| Design Arena: websites | 1336 | 1142 | GPT-6 Astra |
| Design Arena: UI components | 1394 | 1076 | GPT-6 Astra |
| Design Arena: game dev | 1480 | 1079 | GPT-6 Astra |
| Design Arena: data viz | 1334 | 1121 | GPT-6 Astra |
| Design Arena: 3D | 1500 | 1060 | GPT-6 Astra |
| Design Arena: all code categories | 1379 | 1121 | GPT-6 Astra |
| Design Arena: SVG | 1430 | 949 | GPT-6 Astra |
| Design Arena: ASCII art | 1353 | 1062 | GPT-6 Astra |
| LiveBench design | 82.0% | Not measured | Only GPT-6 Astra measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index242
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| Vals Index | 65.0% | Not measured | Only GPT-6 Astra measured |
| LiveBench data analysis | 83.0% | Not measured | Only GPT-6 Astra measured |
| SAGE (Vals AI) | 46.4% | 37.6% | GPT-6 Astra |
| MedScribe (Vals AI) | 87.9% | 67.7% | GPT-6 Astra |
| Vals Multimodal Index | Not measured | 34.8% | Only Mistral Medium 3.5 measured |
| IFBench | Not measured | 68.8% | Only Mistral Medium 3.5 measured |
| Long context reasoning (AA-LCR) | 80.7% | 69.3% | GPT-6 Astra |
| DTBench | 97.3% | 75.5% | GPT-6 Astra |
| LMCA | 64.4% | 26.1% | GPT-6 Astra |
| Surface Evolver Bench | Not measured | 26.9% | Only Mistral Medium 3.5 measured |
| Furniture assembly | 80.0% | Not measured | Only GPT-6 Astra measured |
| LMArena Text | 1441 | 1421 | GPT-6 Astra |
| LMArena Text: instruction following | 1455 | 1415 | GPT-6 Astra |
| LMArena Text: creative writing | 1420 | 1374 | GPT-6 Astra |
| LMArena Vision | 1280 | 1222 | GPT-6 Astra |
| LMArena Text: English | 1447 | 1433 | GPT-6 Astra |
| LMArena Text: non-English | 1432 | 1404 | GPT-6 Astra |
| LMArena Text: Chinese | 1489 | 1444 | GPT-6 Astra |
| LMArena Text: German | 1459 | 1453 | GPT-6 Astra |
| LMArena Text: Japanese | 1405 | Not measured | Only GPT-6 Astra measured |
| LMArena Text: Korean | 1428 | 1384 | GPT-6 Astra |
| LMArena Text: French | 1432 | 1448 | Mistral Medium 3.5 |
| LMArena Text: Spanish | 1422 | 1411 | GPT-6 Astra |
| LMArena Text: Russian | 1438 | 1395 | GPT-6 Astra |
| LMArena Text: Polish | 1422 | 1430 | Mistral Medium 3.5 |
| LMArena Text: multi-turn | 1447 | 1423 | GPT-6 Astra |
| LMArena Text: longer queries | 1460 | 1415 | GPT-6 Astra |
| LMArena Text: writing and language | 1437 | 1384 | GPT-6 Astra |
| LMArena Text: entertainment and media | 1427 | 1382 | GPT-6 Astra |
| LMArena Vision: English | 1280 | 1240 | GPT-6 Astra |
| LMArena Vision: Chinese | 1361 | 1244 | GPT-6 Astra |
| LMArena Vision: reading text | 1292 | 1233 | GPT-6 Astra |
| LMArena Vision: humor | Not measured | 1216 | Only Mistral Medium 3.5 measured |
| LMArena Vision: creative writing | 1286 | 1198 | GPT-6 Astra |
| EQ-Bench 4 | Not measured | 993 | Only Mistral Medium 3.5 measured |
| Neither model has a result on the other 13 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-6 Astra | Mistral Medium 3.5 | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Mistral Medium 3.5 costs less
Repository review
50K input + 3K output tokens
Mistral Medium 3.5 costs less
Agent loop
200K input + 10K output tokens
Mistral Medium 3.5 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | OpenAI GPT-6 Astra | Mistral Medium 3.5 |
|---|---|---|
| Maker | OpenAI | Mistral AI |
| Weights | No public weights listed | No public weights listed |
| Released | September 4, 2026 | April 30, 2026 |
| Context window | 1.05M | 262K |
| Input $/Mtok | $10.00 | $1.50 |
| Output $/Mtok | $50.00 | $7.50 |
| Coding index | 85.1 | 25.5 |
| Independent measurements behind it | 5 | 3 |
| Cost per solved task | Not computable | $6.02 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-6 Astra better than Mistral Medium 3.5 for coding?
Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5. Pick Mistral Medium 3.5 for output tokens 6.7x cheaper ($7.50 vs $50.00 per million) and work measured by LMArena Text: French or LMArena Text: Polish, where it leads.
Which is cheaper, GPT-6 Astra or Mistral Medium 3.5?
GPT-6 Astra costs $10.00 per million input tokens and $50.00 per million output tokens; Mistral Medium 3.5 costs $1.50 and $7.50. Cost per solved task is known for Mistral Medium 3.5 only.
Which has the bigger context window, GPT-6 Astra or Mistral Medium 3.5?
GPT-6 Astra, with 1.05M tokens against 262K.
How many benchmarks is the GPT-6 Astra vs Mistral Medium 3.5 comparison based on?
67 benchmarks have a result for both models as of October 22, 2026. GPT-6 Astra's coding index rests on 5 independent benchmarks and Mistral Medium 3.5's on 3. Where only one model has a result, the page says so instead of naming a winner.