GPT-6 Astra vs Kimi K2.5
Updated October 21, 2026. 72 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick GPT-6 Astra for coding: it scores 88.7 on the Vibe Coding Index against 58.5 for Kimi K2.5.
Pick Kimi K2.5 when output tokens cost 20.0x less, or when what matters is LMArena Text: math or LMArena Text: science, where it leads.
- Shared results
- 72
- GPT-6 Astra only
- 47
- Kimi K2.5 only
- 26
- Like-for-like categories
- 8 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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, four public coding benchmarks
GPT-6 Astra
GPT-6 Astra scores 88.7 against 58.5.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
GPT-6 Astra
GPT-6 Astra leads, 52.7 against 23.5.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only GPT-6 Astra has a AA Agentic Index result, 51.0.
Directional only
Reasoning
GPQA Diamond
No call
Only Kimi K2.5 has a GPQA Diamond result, 84.1%.
Directional only
Math
AIME
No call
Only Kimi K2.5 has a AIME result, 95.6%.
Directional only
Knowledge
MMLU Pro
No call
Only Kimi K2.5 has a MMLU Pro result, 85.9%.
Directional only
Web design
Design Arena: websites
GPT-6 Astra
GPT-6 Astra leads, 1337 against 1249.
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
Kimi K2.5
GPT-6 Astra $0.035, Kimi K2.5 $0.0018 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Kimi K2.5 has the number, $0.24.
Directional only
At a glance
- Coding index
- GPT-6 Astra 88.7 from 2 benchmarks, Kimi K2.5 58.5 from 2 benchmarks.
- Widest category
- Coding, 38.4 points apart on average over 12 shared benchmarks.
- Widest single gap
- Vending-Bench 2: GPT-6 Astra $15,515 against Kimi K2.5 $1,198, 89.5 points apart on a 0 to 100 scale.
- Output price
- GPT-6 Astra $50.00 against Kimi K2.5 $2.50 per million output tokens, 20.0x apart.
- Context window
- GPT-6 Astra takes 1.05M tokens, Kimi K2.5 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 | Kimi K2.5 | Ties |
|---|---|---|---|---|
| Coding | 12 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 8 | 0 | ||
| Reasoning | 9 | 0 | ||
| Math | 1 | 1 | ||
| Knowledge | 4 | 2 | ||
| Web design | 8 | 0 | ||
| General | 15 | 10 | ||
| All shared boards | 59 | 13 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index120
| Benchmark | GPT-6 Astra | Kimi K2.5 | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 70.8% | Only Kimi K2.5 measured |
| SWE-bench Multilingual | Not measured | 67.3% | Only Kimi K2.5 measured |
| LiveBench coding | 93.7% | Not measured | Only GPT-6 Astra measured |
| LMArena WebDev | 1774 | 1437 | GPT-6 Astra |
| AA Coding Index | 76.9 | 46.8 | GPT-6 Astra |
| LiveCodeBench (Vals AI) | Not measured | 83.9% | Only Kimi K2.5 measured |
| SWE-bench Verified (Vals AI) | Not measured | 70.0% | Only Kimi K2.5 measured |
| Terminal-Bench 4 (Vals AI) | 59.6% | Not measured | Only GPT-6 Astra measured |
| Vibe Code Bench (Vals AI) | 89.6% | 17.5% | GPT-6 Astra |
| Code migration (Vals AI) | 67.7% | 7.0% | 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% | 42.0% | 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% | Not measured | Only GPT-6 Astra measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 34.8% | Only Kimi K2.5 measured |
| Terminal-Bench | Not measured | 43.2% | Only Kimi K2.5 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% | 45.6% | GPT-6 Astra |
| MirrorCode | 46.7% | Not measured | Only GPT-6 Astra measured |
| ALE-Bench | 2951.3 | 821.6 | GPT-6 Astra |
| LMArena Text: coding | 1489 | 1483 | GPT-6 Astra |
| LMArena Text: software and IT | 1474 | 1471 | GPT-6 Astra |
| LMArena WebDev: React | 1798 | 1429 | GPT-6 Astra |
| LMArena WebDev: HTML | 1775 | 1426 | GPT-6 Astra |
| LMArena WebDev: from an image | 1726 | 1439 | GPT-6 Astra |
| Neither model has a result on the other 8 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | GPT-6 Astra | Kimi K2.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 52.7 | 23.5 | GPT-6 Astra |
| Epoch Capabilities Index | 168.8 | 148.1 | GPT-6 Astra |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index80
| Benchmark | GPT-6 Astra | Kimi K2.5 | Leader |
|---|---|---|---|
| AA Agentic Index | 51.0 | Not measured | Only GPT-6 Astra measured |
| Design Arena: agents building web apps | 1372 | 1136 | GPT-6 Astra |
| Design Arena: agents building full-stack apps | 1357 | 1114 | GPT-6 Astra |
| Design Arena: agents building mobile apps | 1312 | 1147 | GPT-6 Astra |
| Design Arena: agents building Android apps | Not measured | 1124 | Only Kimi K2.5 measured |
| Design Arena: agents building Godot games | 1348 | 1219 | GPT-6 Astra |
| Design Arena: PowerPoint slides | 1245 | Not measured | Only GPT-6 Astra measured |
| Design Arena: spreadsheets | 1380 | 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% | 35.8% | GPT-6 Astra |
| Tax Agent Bench (Vals AI) | 20.7% | Not measured | Only GPT-6 Astra measured |
| Legal Research Bench (Vals AI) | 39.4% | 15.9% | 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% | 28.5% | 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 | 95.9% | Only Kimi K2.5 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 |
| OSWorld | Not measured | 63.3% | Only Kimi K2.5 measured |
| SpireClimb | 25.7% | Not measured | Only GPT-6 Astra measured |
| Vending-Bench 2 | $15,515 | $1,198 | GPT-6 Astra |
| Neither model has a result on the other 9 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
| Benchmark | GPT-6 Astra | Kimi K2.5 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 84.1% | Only Kimi K2.5 measured |
| LiveBench reasoning | 92.7% | Not measured | Only GPT-6 Astra measured |
| MysteryMechanism (Vals AI) | 53.1% | Not measured | Only GPT-6 Astra measured |
| MMMU Pro (Vals AI) | Not measured | 84.3% | Only Kimi K2.5 measured |
| GPQA Diamond (Artificial Analysis run) | 96.3% | 87.9% | GPT-6 Astra |
| Humanity's Last Exam (Artificial Analysis run) | 54.7% | 30.7% | GPT-6 Astra |
| GPQA Diamond (Epoch AI run) | 95.8% | Not measured | Only GPT-6 Astra measured |
| ARC-AGI | 98.5% | 65.3% | GPT-6 Astra |
| ARC-AGI-2 | 95.0% | 11.8% | GPT-6 Astra |
| SimpleBench | Not measured | 46.8% | Only Kimi K2.5 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 | 1453 | GPT-6 Astra |
| LMArena Text: expert | 1489 | 1466 | GPT-6 Astra |
| LMArena Text: hard prompts in English | 1464 | 1460 | GPT-6 Astra |
| LMArena Vision: diagrams | 1297 | 1282 | GPT-6 Astra |
| LMArena Vision: homework | 1337 | 1297 | GPT-6 Astra |
| Neither model has a result on the other 3 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | GPT-6 Astra | Kimi K2.5 | Leader |
|---|---|---|---|
| AIME | Not measured | 95.6% | Only Kimi K2.5 measured |
| 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% | Not measured | Only GPT-6 Astra measured |
| LMArena Text: math | 1465 | 1470 | Kimi K2.5 |
| LMArena Text: mathematical work | 1484 | 1473 | GPT-6 Astra |
| Neither model has a result on the other 6 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index42
| Benchmark | GPT-6 Astra | Kimi K2.5 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 85.9% | Only Kimi K2.5 measured |
| CaseLaw (Vals AI) | Not measured | 58.7% | Only Kimi K2.5 measured |
| CorpFin (Vals AI) | Not measured | 68.3% | Only Kimi K2.5 measured |
| TaxEval (Vals AI) | Not measured | 74.2% | Only Kimi K2.5 measured |
| MortgageTax (Vals AI) | Not measured | 66.5% | Only Kimi K2.5 measured |
| MedQA (Vals AI) | Not measured | 94.4% | Only Kimi K2.5 measured |
| MedCode (Vals AI) | 48.5% | 39.3% | GPT-6 Astra |
| SimpleQA Verified | 75.6% | 34.3% | GPT-6 Astra |
| LMArena Text: science | 1451 | 1459 | Kimi K2.5 |
| LMArena Text: medicine and healthcare | 1425 | 1448 | Kimi K2.5 |
| LMArena Text: legal and government | 1462 | 1441 | GPT-6 Astra |
| LMArena Text: business and finance | 1439 | 1427 | GPT-6 Astra |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index80
| Benchmark | GPT-6 Astra | Kimi K2.5 | Leader |
|---|---|---|---|
| Design Arena: websites | 1337 | 1249 | GPT-6 Astra |
| Design Arena: UI components | 1394 | 1236 | GPT-6 Astra |
| Design Arena: game dev | 1474 | 1207 | GPT-6 Astra |
| Design Arena: data viz | 1335 | 1219 | GPT-6 Astra |
| Design Arena: 3D | 1501 | 1205 | GPT-6 Astra |
| Design Arena: all code categories | 1379 | 1236 | GPT-6 Astra |
| Design Arena: SVG | 1431 | 1149 | GPT-6 Astra |
| Design Arena: ASCII art | 1359 | 1165 | 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 index1510
| Benchmark | GPT-6 Astra | Kimi K2.5 | 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% | 49.9% | Kimi K2.5 |
| MedScribe (Vals AI) | 87.9% | 76.4% | GPT-6 Astra |
| IFBench | Not measured | 70.2% | Only Kimi K2.5 measured |
| Long context reasoning (AA-LCR) | 80.7% | 78.0% | GPT-6 Astra |
| DTBench | 97.3% | Not measured | Only GPT-6 Astra measured |
| LMCA | 64.4% | Not measured | Only GPT-6 Astra measured |
| Fiction.LiveBench | Not measured | 86.1% | Only Kimi K2.5 measured |
| CL-bench | Not measured | 19.3% | Only Kimi K2.5 measured |
| Furniture assembly | 80.0% | Not measured | Only GPT-6 Astra measured |
| CL-bench Life | Not measured | 13.2% | Only Kimi K2.5 measured |
| LMArena Text | 1441 | 1445 | Kimi K2.5 |
| LMArena Text: instruction following | 1455 | 1431 | GPT-6 Astra |
| LMArena Text: creative writing | 1420 | 1422 | Kimi K2.5 |
| LMArena Vision | 1280 | 1269 | GPT-6 Astra |
| LMArena Text: English | 1447 | 1453 | Kimi K2.5 |
| LMArena Text: non-English | 1432 | 1433 | Kimi K2.5 |
| LMArena Text: Chinese | 1489 | 1494 | Kimi K2.5 |
| LMArena Text: German | 1459 | 1441 | GPT-6 Astra |
| LMArena Text: Japanese | 1405 | 1423 | Kimi K2.5 |
| LMArena Text: Korean | 1428 | 1412 | GPT-6 Astra |
| LMArena Text: French | 1432 | 1454 | Kimi K2.5 |
| LMArena Text: Spanish | 1422 | 1450 | Kimi K2.5 |
| LMArena Text: Russian | 1438 | 1435 | GPT-6 Astra |
| LMArena Text: Polish | 1422 | 1445 | Kimi K2.5 |
| LMArena Text: multi-turn | 1447 | 1444 | GPT-6 Astra |
| LMArena Text: longer queries | 1460 | 1445 | GPT-6 Astra |
| LMArena Text: writing and language | 1437 | 1425 | GPT-6 Astra |
| LMArena Text: entertainment and media | 1427 | 1417 | GPT-6 Astra |
| LMArena Vision: English | 1280 | 1274 | GPT-6 Astra |
| LMArena Vision: Chinese | 1361 | 1328 | GPT-6 Astra |
| LMArena Vision: reading text | 1292 | 1276 | GPT-6 Astra |
| LMArena Vision: humor | Not measured | 1284 | Only Kimi K2.5 measured |
| LMArena Vision: captioning | Not measured | 1257 | Only Kimi K2.5 measured |
| LMArena Vision: recognizing things | Not measured | 1285 | Only Kimi K2.5 measured |
| LMArena Vision: creative writing | 1286 | 1269 | GPT-6 Astra |
| Neither model has a result on the other 9 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-6 Astra | Kimi K2.5 | 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
Kimi K2.5 costs less
Repository review
50K input + 3K output tokens
Kimi K2.5 costs less
Agent loop
200K input + 10K output tokens
Kimi K2.5 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 | MoonshotAI Kimi K2.5 |
|---|---|---|
| Maker | OpenAI | Moonshot AI |
| Weights | No public weights listed | Open weights |
| Released | September 4, 2026 | January 27, 2026 |
| Context window | 1.05M | 262K |
| Input $/Mtok | $10.00 | $0.50 |
| Output $/Mtok | $50.00 | $2.50 |
| Coding index | 88.7 | 58.5 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | Not computable | $0.24 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-6 Astra better than Kimi K2.5 for coding?
Pick GPT-6 Astra for coding: it scores 88.7 on the Vibe Coding Index against 58.5 for Kimi K2.5. Pick Kimi K2.5 when output tokens cost 20.0x less, or when what matters is LMArena Text: math or LMArena Text: science, where it leads.
Which is cheaper, GPT-6 Astra or Kimi K2.5?
GPT-6 Astra costs $10.00 per million input tokens and $50.00 per million output tokens; Kimi K2.5 costs $0.50 and $2.50. Cost per solved task is known for Kimi K2.5 only.
Which has the bigger context window, GPT-6 Astra or Kimi K2.5?
GPT-6 Astra, with 1.05M tokens against 262K.
How many benchmarks is the GPT-6 Astra vs Kimi K2.5 comparison based on?
72 benchmarks have a result for both models as of October 21, 2026. GPT-6 Astra's coding index rests on 2 independent benchmarks and Kimi K2.5's on 2. Where only one model has a result, the page says so instead of naming a winner.