GPT-5.1-Codex vs GPT-6 Astra
GPT-6 Astra leads GPT-5.1-Codex on coding, 85.1 to 15.3 on the Vibe Coding Index, and GPT-5.1-Codex costs 5.0x less per output token ($10.00 vs $50.00 per million). Updated October 22, 2026; 16 benchmarks have a result for both.
vs boards won of 16 shared
GPT-5.1-Codex or GPT-6 Astra: which to pick
Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 15.3 for GPT-5.1-Codex.
Pick GPT-5.1-Codex for output tokens 5.0x cheaper ($10.00 vs $50.00 per million).
Model AGPT-5.1-CodexOpenAI15.3/1002 independent benchmarks$0.892 per solved taskModel BGPT-6 AstraOpenAI85.1/1005 independent benchmarksNo cost per solved task
- Shared results
- 16
- GPT-5.1-Codex only
- 10
- GPT-6 Astra only
- 105
- Like-for-like categories
- 6 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 15.3.
2 and 5 benchmarks behind the scores
Intelligence
AA Intelligence Index
GPT-6 Astra
GPT-6 Astra leads, 52.7 against 23.7.
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
Web design
Design Arena: websites
GPT-6 Astra
GPT-6 Astra leads, 1336 against 1161.
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 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5.1-Codex
GPT-5.1-Codex $0.0063, GPT-6 Astra $0.035 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.1-Codex has the number, $0.892.
Directional only
At a glance
- Coding index
- GPT-5.1-Codex 15.3 from 2 benchmarks, GPT-6 Astra 85.1 from 5 benchmarks.
- Widest category
- Coding, 59.5 points apart on average over 4 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): GPT-5.1-Codex 13.1% against GPT-6 Astra 89.6%, 76.5 points apart on a 0 to 100 scale.
- Output price
- GPT-5.1-Codex $10.00 against GPT-6 Astra $50.00 per million output tokens, 5.0x apart.
- Context window
- GPT-5.1-Codex takes 400K tokens, GPT-6 Astra 1.05M.
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-5.1-Codex | Bars | GPT-6 Astra | Ties |
|---|---|---|---|---|
| Coding | 0 | 4 | ||
| Intelligence | 0 | 1 | ||
| Agentic work | 0 | 3 | ||
| Reasoning | 0 | 2 | ||
| Web design | 0 | 5 | ||
| General | 0 | 1 | ||
| All shared boards | 0 | 16 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index04
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| SWE-bench Verified | 66.0% | Not measured | Only GPT-5.1-Codex measured |
| LiveBench coding | Not measured | 93.7% | Only GPT-6 Astra measured |
| LMArena WebDev | 1337 | 1774 | GPT-6 Astra |
| AA Coding Index | Not measured | 76.9 | Only GPT-6 Astra measured |
| LiveCodeBench (Vals AI) | 85.5% | Not measured | Only GPT-5.1-Codex measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 59.6% | Only GPT-6 Astra measured |
| Vibe Code Bench (Vals AI) | 13.1% | 89.6% | GPT-6 Astra |
| Code migration (Vals AI) | Not measured | 67.7% | Only GPT-6 Astra measured |
| ProgramBench (Vals AI) | Not measured | 5.5% | Only GPT-6 Astra measured |
| IOI (Vals AI) | Not measured | 100.0% | Only GPT-6 Astra measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 87.3% | Only GPT-6 Astra measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 43.3% | Only GPT-6 Astra measured |
| Vibe Code Bench 1-100 (Vals AI) | Not measured | 27.6% | Only GPT-6 Astra measured |
| CyberBench (Vals AI) | Not measured | 41.1% | Only GPT-6 Astra measured |
| LiveCodeBench (Artificial Analysis run) | 84.9% | Not measured | Only GPT-5.1-Codex measured |
| SciCode | Not measured | 56.5% | Only GPT-6 Astra measured |
| Terminal-Bench Hard (Artificial Analysis run) | 34.8% | Not measured | Only GPT-5.1-Codex measured |
| Terminal-Bench | 57.8% | Not measured | Only GPT-5.1-Codex measured |
| FrontierCode | Not measured | 53.3% | Only GPT-6 Astra measured |
| FrontierSWE | Not measured | 65.5% | Only GPT-6 Astra measured |
| GSO-Bench | Not measured | 79.4% | Only GPT-6 Astra measured |
| WeirdML | Not measured | 93.3% | Only GPT-6 Astra measured |
| MirrorCode | Not measured | 46.7% | Only GPT-6 Astra measured |
| ALE-Bench | 1244.9 | 2951.3 | GPT-6 Astra |
| LMArena Text: coding | Not measured | 1489 | Only GPT-6 Astra measured |
| LMArena Text: software and IT | Not measured | 1474 | Only GPT-6 Astra measured |
| LMArena WebDev: React | Not measured | 1798 | Only GPT-6 Astra measured |
| LMArena WebDev: HTML | 1346 | 1775 | GPT-6 Astra |
| LMArena WebDev: from an image | Not measured | 1726 | Only GPT-6 Astra measured |
| SciCode | Not measured | 12.3% | Only GPT-6 Astra measured |
| Neither model has a result on the other 9 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| AA Intelligence Index | 23.7 | 52.7 | GPT-6 Astra |
| Epoch Capabilities Index | Not measured | 168.8 | Only GPT-6 Astra measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 51.0 | Only GPT-6 Astra measured |
| Design Arena: agents building web apps | 1018 | 1373 | GPT-6 Astra |
| Design Arena: agents building full-stack apps | 1086 | 1357 | GPT-6 Astra |
| Design Arena: agents building mobile apps | 1191 | 1312 | GPT-6 Astra |
| Design Arena: agents building Godot games | Not measured | 1348 | Only GPT-6 Astra measured |
| Design Arena: PowerPoint slides | Not measured | 1219 | Only GPT-6 Astra measured |
| Design Arena: spreadsheets | Not measured | 1365 | Only GPT-6 Astra measured |
| LiveBench research | Not measured | 85.2% | Only GPT-6 Astra measured |
| LiveBench browser | Not measured | 84.0% | Only GPT-6 Astra measured |
| LiveBench long agentic | Not measured | 82.4% | Only GPT-6 Astra measured |
| SREBench (Vals AI) | Not measured | 56.9% | Only GPT-6 Astra measured |
| Finance Agent (Vals AI) | Not measured | 53.5% | Only GPT-6 Astra measured |
| Tax Agent Bench (Vals AI) | Not measured | 20.7% | Only GPT-6 Astra measured |
| Legal Research Bench (Vals AI) | Not measured | 39.4% | Only GPT-6 Astra measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 7.1% | Only GPT-6 Astra measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 71.7% | Only GPT-6 Astra measured |
| BioMysteryBench (Vals AI) | Not measured | 79.3% | Only GPT-6 Astra measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 62.9% | Only GPT-6 Astra measured |
| Vals Science Index | Not measured | 65.1% | Only GPT-6 Astra measured |
| Time Horizon Index (Vals AI) | Not measured | 90.5% | Only GPT-6 Astra measured |
| CUA-bench (Vals AI) | Not measured | 19.2% | Only GPT-6 Astra measured |
| Robo-bench (Vals AI) | Not measured | 23.3% | Only GPT-6 Astra measured |
| τ²-Bench Telecom | 83.0% | Not measured | Only GPT-5.1-Codex measured |
| APEX-Agents | Not measured | 64.7% | Only GPT-6 Astra measured |
| Remote Labor Index | Not measured | 20.8% | Only GPT-6 Astra measured |
| BALROG | Not measured | 68.3% | Only GPT-6 Astra measured |
| SpireClimb | Not measured | 25.7% | Only GPT-6 Astra measured |
| Vending-Bench 2 | Not measured | $15,515 | Only GPT-6 Astra measured |
| Neither model has a result on the other 13 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| LiveBench reasoning | Not measured | 92.7% | Only GPT-6 Astra measured |
| MysteryMechanism (Vals AI) | Not measured | 53.1% | Only GPT-6 Astra measured |
| GPQA Diamond (Artificial Analysis run) | 86.0% | 96.3% | GPT-6 Astra |
| Humanity's Last Exam (Artificial Analysis run) | 25.7% | 54.7% | GPT-6 Astra |
| GPQA Diamond (Epoch AI run) | Not measured | 95.8% | Only GPT-6 Astra measured |
| ARC-AGI | Not measured | 98.5% | Only GPT-6 Astra measured |
| ARC-AGI-2 | Not measured | 95.0% | Only GPT-6 Astra measured |
| Chess puzzles | Not measured | 74.0% | Only GPT-6 Astra measured |
| Mystery game puzzles | Not measured | 84.0% | Only GPT-6 Astra measured |
| EBR-bench | Not measured | 76.2% | Only GPT-6 Astra measured |
| LMArena Text: hard prompts | Not measured | 1463 | Only GPT-6 Astra measured |
| LMArena Text: expert | Not measured | 1489 | Only GPT-6 Astra measured |
| LMArena Text: hard prompts in English | Not measured | 1464 | Only GPT-6 Astra measured |
| LMArena Vision: diagrams | Not measured | 1297 | Only GPT-6 Astra measured |
| LMArena Vision: homework | Not measured | 1337 | Only GPT-6 Astra measured |
| Neither model has a result on the other 7 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| AA Math Index | 95.7 | Not measured | Only GPT-5.1-Codex measured |
| AIME 2025 (Artificial Analysis run) | 95.7% | Not measured | Only GPT-5.1-Codex measured |
| OTIS Mock AIME | Not measured | 100.0% | Only GPT-6 Astra measured |
| FrontierMath, tiers 1 to 3 | Not measured | 93.7% | Only GPT-6 Astra measured |
| FrontierMath, tier 4 | Not measured | 97.6% | Only GPT-6 Astra measured |
| ProofBench | Not measured | 99.0% | Only GPT-6 Astra measured |
| LMArena Text: math | Not measured | 1465 | Only GPT-6 Astra measured |
| LMArena Text: mathematical work | Not measured | 1484 | Only GPT-6 Astra measured |
| Neither model has a result on the other 5 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| MedCode (Vals AI) | Not measured | 48.5% | Only GPT-6 Astra measured |
| MMLU Pro (Artificial Analysis run) | 86.0% | Not measured | Only GPT-5.1-Codex measured |
| SimpleQA Verified | Not measured | 75.6% | Only GPT-6 Astra measured |
| LMArena Text: science | Not measured | 1451 | Only GPT-6 Astra measured |
| LMArena Text: medicine and healthcare | Not measured | 1425 | Only GPT-6 Astra measured |
| LMArena Text: legal and government | Not measured | 1462 | Only GPT-6 Astra measured |
| LMArena Text: business and finance | Not measured | 1439 | Only GPT-6 Astra measured |
| FACTS Benchmark Suite | Not measured | 75.7% | Only GPT-6 Astra measured |
| Neither model has a result on the other 10 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| Design Arena: websites | 1161 | 1336 | GPT-6 Astra |
| Design Arena: UI components | 1234 | 1393 | GPT-6 Astra |
| Design Arena: game dev | 1137 | 1478 | GPT-6 Astra |
| Design Arena: data viz | 1213 | 1335 | GPT-6 Astra |
| Design Arena: 3D | Not measured | 1500 | Only GPT-6 Astra measured |
| Design Arena: all code categories | 1152 | 1379 | GPT-6 Astra |
| Design Arena: SVG | Not measured | 1431 | Only GPT-6 Astra measured |
| Design Arena: ASCII art | Not measured | 1353 | Only GPT-6 Astra measured |
| LiveBench design | Not measured | 82.0% | Only GPT-6 Astra measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | Leader |
|---|---|---|---|
| Vals Index | Not measured | 65.0% | Only GPT-6 Astra measured |
| LiveBench data analysis | Not measured | 83.0% | Only GPT-6 Astra measured |
| SAGE (Vals AI) | Not measured | 46.4% | Only GPT-6 Astra measured |
| MedScribe (Vals AI) | Not measured | 87.9% | Only GPT-6 Astra measured |
| IFBench | 70.0% | Not measured | Only GPT-5.1-Codex measured |
| Long context reasoning (AA-LCR) | 69.3% | 80.7% | GPT-6 Astra |
| DTBench | Not measured | 97.3% | Only GPT-6 Astra measured |
| LMCA | Not measured | 64.4% | Only GPT-6 Astra measured |
| Furniture assembly | Not measured | 80.0% | Only GPT-6 Astra measured |
| LMArena Text | Not measured | 1441 | Only GPT-6 Astra measured |
| LMArena Text: instruction following | Not measured | 1455 | Only GPT-6 Astra measured |
| LMArena Text: creative writing | Not measured | 1420 | Only GPT-6 Astra measured |
| LMArena Vision | Not measured | 1280 | Only GPT-6 Astra measured |
| LMArena Text: English | Not measured | 1447 | Only GPT-6 Astra measured |
| LMArena Text: non-English | Not measured | 1432 | Only GPT-6 Astra measured |
| LMArena Text: Chinese | Not measured | 1489 | Only GPT-6 Astra measured |
| LMArena Text: German | Not measured | 1459 | Only GPT-6 Astra measured |
| LMArena Text: Japanese | Not measured | 1405 | Only GPT-6 Astra measured |
| LMArena Text: Korean | Not measured | 1428 | Only GPT-6 Astra measured |
| LMArena Text: French | Not measured | 1432 | Only GPT-6 Astra measured |
| LMArena Text: Spanish | Not measured | 1422 | Only GPT-6 Astra measured |
| LMArena Text: Russian | Not measured | 1438 | Only GPT-6 Astra measured |
| LMArena Text: Polish | Not measured | 1422 | Only GPT-6 Astra measured |
| LMArena Text: multi-turn | Not measured | 1447 | Only GPT-6 Astra measured |
| LMArena Text: longer queries | Not measured | 1460 | Only GPT-6 Astra measured |
| LMArena Text: writing and language | Not measured | 1437 | Only GPT-6 Astra measured |
| LMArena Text: entertainment and media | Not measured | 1427 | Only GPT-6 Astra measured |
| LMArena Vision: English | Not measured | 1280 | Only GPT-6 Astra measured |
| LMArena Vision: Chinese | Not measured | 1361 | Only GPT-6 Astra measured |
| LMArena Vision: reading text | Not measured | 1292 | Only GPT-6 Astra measured |
| LMArena Vision: creative writing | Not measured | 1286 | Only GPT-6 Astra measured |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-5.1-Codex | GPT-6 Astra | 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
GPT-5.1-Codex$0.0063Fits in one request
GPT-6 Astra$0.035Fits in one request
GPT-5.1-Codex costs less
Repository review
50K input + 3K output tokens
GPT-5.1-Codex$0.092Fits in one request
GPT-6 Astra$0.650Fits in one request
GPT-5.1-Codex costs less
Agent loop
200K input + 10K output tokens
GPT-5.1-Codex$0.350Fits in one request
GPT-6 Astra$2.50Fits in one request
GPT-5.1-Codex 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-5.1-Codex | OpenAI GPT-6 Astra |
|---|---|---|
| Maker | OpenAI | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | November 13, 2025 | September 4, 2026 |
| Context window | 400K | 1.05M |
| Input $/Mtok | $1.25 | $10.00 |
| Output $/Mtok | $10.00 | $50.00 |
| Coding index | 15.3 | 85.1 |
| Independent measurements behind it | 2 | 5 |
| Cost per solved task | $0.892 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5.1-Codex better than GPT-6 Astra for coding?
Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 15.3 for GPT-5.1-Codex. Pick GPT-5.1-Codex for output tokens 5.0x cheaper ($10.00 vs $50.00 per million).
Which is cheaper, GPT-5.1-Codex or GPT-6 Astra?
GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens; GPT-6 Astra costs $10.00 and $50.00. Cost per solved task is known for GPT-5.1-Codex only.
Which has the bigger context window, GPT-5.1-Codex or GPT-6 Astra?
GPT-6 Astra, with 1.05M tokens against 400K.
How many benchmarks is the GPT-5.1-Codex vs GPT-6 Astra comparison based on?
16 benchmarks have a result for both models as of October 22, 2026. GPT-5.1-Codex's coding index rests on 2 independent benchmarks and GPT-6 Astra's on 5. Where only one model has a result, the page says so instead of naming a winner.