GPT-5.1 vs Inkling
GPT-5.1 leads Inkling on coding, 40.4 to 31.5 on the Vibe Coding Index, and Inkling costs 2.5x less per output token ($4.05 vs $10.00 per million). Updated October 21, 2026; 68 benchmarks have a result for both.
GPT-5.1 or Inkling: which to pick
Pick GPT-5.1 for coding: it scores 40.4 on the Vibe Coding Index against 31.5 for Inkling, though on 3 benchmarks against 6.
Pick Inkling for output tokens 2.5x cheaper ($4.05 vs $10.00 per million) and a lower cost per solved task ($0.76 against $1.02).
- Shared results
- 68
- GPT-5.1 only
- 33
- Inkling only
- 34
- Like-for-like categories
- 7 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-5.1
GPT-5.1 scores 40.4 against 31.5.
3 and 6 benchmarks behind the scores
Intelligence
AA Intelligence Index
Inkling
Inkling leads, 25.0 against 24.7.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Inkling has a AA Agentic Index result, 22.5.
Directional only
Reasoning
GPQA Diamond
Inkling
Inkling leads, 87.1% against 86.6%.
Same board, both measured
Math
AIME
No call
Only GPT-5.1 has a AIME result, 93.3%.
Directional only
Knowledge
MMLU Pro
GPT-5.1
GPT-5.1 leads, 86.4% against 86.3%.
Same board, both measured
Web design
Design Arena: websites
Inkling
Inkling leads, 1224 against 1187.
Same board, both measured
General
Vals Index
No call
Only Inkling has a Vals Index result, 29.0%.
Directional only
Long documents
Listed context window
Inkling
Inkling takes 524K tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling
GPT-5.1 $0.0063, Inkling $0.0030 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Inkling
GPT-5.1 $1.02, Inkling $0.76.
Published attempt cost and pass rate
At a glance
- Coding index
- GPT-5.1 40.4 from 3 benchmarks, Inkling 31.5 from 6 benchmarks.
- Widest category
- Coding, 6.9 points apart on average over 10 shared benchmarks.
- Widest single gap
- WeirdML: GPT-5.1 60.8% against Inkling 32.3%, 28.5 points apart on a 0 to 100 scale.
- Output price
- GPT-5.1 $10.00 against Inkling $4.05 per million output tokens, 2.5x apart.
- Context window
- GPT-5.1 takes 400K tokens, Inkling 524K.
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 | Bars | Inkling | Ties |
|---|---|---|---|---|
| Coding | 4 | 6 | ||
| Intelligence | 1 | 1 | ||
| Reasoning | 7 | 5 | ||
| Math | 0 | 3 | ||
| Knowledge | 7 | 4 | ||
| Web design | 4 | 4 | ||
| General | 16 | 6 | ||
| All shared boards | 39 | 29 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index46
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| SWE-bench Verified | 66.0% | Not measured | Only GPT-5.1 measured |
| LiveBench coding | Not measured | 64.0% | Only Inkling measured |
| LMArena WebDev | 1396 | 1414 | Inkling |
| AA Coding Index | 49.4 | 52.1 | Inkling |
| LiveCodeBench (Vals AI) | 86.5% | 85.5% | GPT-5.1 |
| SWE-bench Verified (Vals AI) | 69.8% | 77.6% | Inkling |
| Terminal-Bench 4 (Vals AI) | Not measured | 0.5% | Only Inkling measured |
| Vibe Code Bench (Vals AI) | 24.6% | 19.2% | GPT-5.1 |
| Code migration (Vals AI) | Not measured | 11.8% | Only Inkling measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Inkling measured |
| IOI (Vals AI) | Not measured | 14.9% | Only Inkling measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 47.6% | Only Inkling measured |
| Vibe Code Bench 1-100 (Vals AI) | Not measured | 7.3% | Only Inkling measured |
| SkillsBench (Vals AI) | Not measured | 26.1% | Only Inkling measured |
| CyberBench (Vals AI) | Not measured | 66.8% | Only Inkling measured |
| LiveCodeBench (Artificial Analysis run) | 86.8% | Not measured | Only GPT-5.1 measured |
| SciCode | Not measured | 47.0% | Only Inkling measured |
| Terminal-Bench Hard (Artificial Analysis run) | 45.5% | Not measured | Only GPT-5.1 measured |
| Terminal-Bench | 47.6% | Not measured | Only GPT-5.1 measured |
| FrontierCode | Not measured | 14.0% | Only Inkling measured |
| FrontierSWE | Not measured | 4.1% | Only Inkling measured |
| GSO-Bench | 13.7% | Not measured | Only GPT-5.1 measured |
| WeirdML | 60.8% | 32.3% | GPT-5.1 |
| ALE-Bench | Not measured | 946.0 | Only Inkling measured |
| LMArena Text: coding | 1453 | 1466 | Inkling |
| LMArena Text: software and IT | 1454 | 1465 | Inkling |
| LMArena WebDev: React | 1307 | 1404 | Inkling |
| LMArena WebDev: HTML | 1405 | 1399 | GPT-5.1 |
| LMArena WebDev: from an image | 1421 | Not measured | Only GPT-5.1 measured |
| Neither model has a result on the other 10 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| AA Intelligence Index | 24.7 | 25.0 | Inkling |
| Epoch Capabilities Index | 149.8 | 148.4 | GPT-5.1 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index15 boards, none shared
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 22.5 | Only Inkling measured |
| Design Arena: agents building web apps | Not measured | 1196 | Only Inkling measured |
| LiveBench research | Not measured | 59.9% | Only Inkling measured |
| LiveBench browser | Not measured | 16.0% | Only Inkling measured |
| LiveBench long agentic | Not measured | 14.1% | Only Inkling measured |
| SREBench (Vals AI) | Not measured | 0.0% | Only Inkling measured |
| Finance Agent (Vals AI) | Not measured | 46.6% | Only Inkling measured |
| Tax Agent Bench (Vals AI) | Not measured | 15.3% | Only Inkling measured |
| Legal Research Bench (Vals AI) | Not measured | 28.4% | Only Inkling measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 3.8% | Only Inkling measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 38.4% | Only Inkling measured |
| τ²-Bench Telecom | 81.9% | Not measured | Only GPT-5.1 measured |
| APEX-Agents | Not measured | 33.8% | Only Inkling measured |
| DeepResearch Bench | 42.8% | Not measured | Only GPT-5.1 measured |
| Vending-Bench 2 | $1,473 | Not measured | Only GPT-5.1 measured |
| Neither model has a result on the other 26 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index75
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| GPQA Diamond | 86.6% | 87.1% | Inkling |
| LiveBench reasoning | Not measured | 78.3% | Only Inkling measured |
| MMMU Pro (Vals AI) | 83.2% | 78.5% | GPT-5.1 |
| GPQA Diamond (Artificial Analysis run) | 87.3% | 87.2% | GPT-5.1 |
| Humanity's Last Exam (Artificial Analysis run) | 28.5% | 31.9% | Inkling |
| GPQA Diamond (Epoch AI run) | 87.6% | 88.3% | Inkling |
| ARC-AGI | 72.8% | 79.5% | Inkling |
| ARC-AGI-2 | 17.6% | 36.5% | Inkling |
| SimpleBench | 53.2% | 50.0% | GPT-5.1 |
| Chess puzzles | 42.0% | 21.0% | GPT-5.1 |
| Mystery game puzzles | 19.0% | Not measured | Only GPT-5.1 measured |
| VPCT | 58.7% | Not measured | Only GPT-5.1 measured |
| LMArena Text: hard prompts | 1457 | 1451 | GPT-5.1 |
| LMArena Text: expert | 1470 | 1466 | GPT-5.1 |
| LMArena Text: hard prompts in English | 1462 | 1448 | GPT-5.1 |
| LMArena Vision: diagrams | 1264 | Not measured | Only GPT-5.1 measured |
| LMArena Vision: homework | 1272 | Not measured | Only GPT-5.1 measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| AIME | 93.3% | Not measured | Only GPT-5.1 measured |
| MGSM (Vals AI) | 93.0% | Not measured | Only GPT-5.1 measured |
| AA Math Index | 94.0 | Not measured | Only GPT-5.1 measured |
| AIME 2025 (Artificial Analysis run) | 94.0% | Not measured | Only GPT-5.1 measured |
| OTIS Mock AIME | 88.6% | 88.9% | Inkling |
| FrontierMath, tiers 1 to 3 | Not measured | 33.3% | Only Inkling measured |
| FrontierMath, tier 4 | Not measured | 4.9% | Only Inkling measured |
| ProofBench | Not measured | 0.0% | Only Inkling measured |
| LMArena Text: math | 1446 | 1479 | Inkling |
| LMArena Text: mathematical work | 1449 | 1460 | Inkling |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index74
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| MMLU Pro | 86.4% | 86.3% | GPT-5.1 |
| LegalBench (Vals AI) | 85.7% | 83.0% | GPT-5.1 |
| CaseLaw (Vals AI) | 73.4% | Not measured | Only GPT-5.1 measured |
| CorpFin (Vals AI) | 63.8% | 68.6% | Inkling |
| TaxEval (Vals AI) | 74.9% | 75.3% | Inkling |
| MortgageTax (Vals AI) | 61.4% | 64.0% | Inkling |
| MedQA (Vals AI) | 96.4% | Not measured | Only GPT-5.1 measured |
| MedCode (Vals AI) | 52.7% | 41.2% | GPT-5.1 |
| MMLU Pro (Artificial Analysis run) | 87.0% | Not measured | Only GPT-5.1 measured |
| SimpleQA Verified | 48.0% | 40.3% | GPT-5.1 |
| LMArena Text: science | 1459 | 1455 | GPT-5.1 |
| LMArena Text: medicine and healthcare | 1456 | 1447 | GPT-5.1 |
| LMArena Text: legal and government | 1459 | 1448 | GPT-5.1 |
| LMArena Text: business and finance | 1431 | 1438 | Inkling |
| FACTS Benchmark Suite | 45.0% | Not measured | Only GPT-5.1 measured |
| Neither model has a result on the other 3 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index44
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| Design Arena: websites | 1187 | 1224 | Inkling |
| Design Arena: UI components | 1166 | 1201 | Inkling |
| Design Arena: game dev | 1179 | 1166 | GPT-5.1 |
| Design Arena: data viz | 1204 | 1159 | GPT-5.1 |
| Design Arena: 3D | 1061 | 1161 | Inkling |
| Design Arena: all code categories | 1171 | 1206 | Inkling |
| Design Arena: SVG | 1149 | 1110 | GPT-5.1 |
| Design Arena: ASCII art | 1119 | 1089 | GPT-5.1 |
| LiveBench design | Not measured | 58.3% | Only Inkling measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index166
| Benchmark | GPT-5.1 | Inkling | Leader |
|---|---|---|---|
| Vals Index | Not measured | 29.0% | Only Inkling measured |
| LiveBench data analysis | Not measured | 72.8% | Only Inkling measured |
| Public Benefits Bench (Vals AI) | Not measured | 58.5% | Only Inkling measured |
| SAGE (Vals AI) | 43.2% | 36.5% | GPT-5.1 |
| MedScribe (Vals AI) | 88.1% | 85.4% | GPT-5.1 |
| Vals Multimodal Index | Not measured | 49.4% | Only Inkling measured |
| IFBench | 72.9% | Not measured | Only GPT-5.1 measured |
| Long context reasoning (AA-LCR) | 80.0% | 77.3% | GPT-5.1 |
| DTBench | 90.1% | 87.5% | GPT-5.1 |
| LMCA | 43.9% | 37.6% | GPT-5.1 |
| CL-bench | 23.7% | Not measured | Only GPT-5.1 measured |
| CL-bench Life | 17.3% | Not measured | Only GPT-5.1 measured |
| LMArena Text | 1443 | 1442 | GPT-5.1 |
| LMArena Text: instruction following | 1443 | 1425 | GPT-5.1 |
| LMArena Text: creative writing | 1427 | 1390 | GPT-5.1 |
| LMArena Vision | 1250 | Not measured | Only GPT-5.1 measured |
| LMArena Text: English | 1451 | 1442 | GPT-5.1 |
| LMArena Text: non-English | 1431 | 1434 | Inkling |
| LMArena Text: Chinese | 1495 | 1493 | GPT-5.1 |
| LMArena Text: German | 1438 | 1445 | Inkling |
| LMArena Text: Japanese | 1453 | 1429 | GPT-5.1 |
| LMArena Text: Korean | 1401 | 1403 | Inkling |
| LMArena Text: French | 1450 | 1455 | Inkling |
| LMArena Text: Spanish | 1433 | 1449 | Inkling |
| LMArena Text: Russian | 1435 | 1430 | GPT-5.1 |
| LMArena Text: Polish | 1440 | 1450 | Inkling |
| LMArena Text: multi-turn | 1450 | 1437 | GPT-5.1 |
| LMArena Text: longer queries | 1448 | 1435 | GPT-5.1 |
| LMArena Text: writing and language | 1428 | 1404 | GPT-5.1 |
| LMArena Text: entertainment and media | 1415 | 1394 | GPT-5.1 |
| LMArena Vision: English | 1252 | Not measured | Only GPT-5.1 measured |
| LMArena Vision: Chinese | 1270 | Not measured | Only GPT-5.1 measured |
| LMArena Vision: reading text | 1255 | Not measured | Only GPT-5.1 measured |
| LMArena Vision: humor | 1263 | Not measured | Only GPT-5.1 measured |
| LMArena Vision: captioning | 1252 | Not measured | Only GPT-5.1 measured |
| LMArena Vision: recognizing things | 1232 | Not measured | Only GPT-5.1 measured |
| LMArena Vision: creative writing | 1266 | Not measured | Only GPT-5.1 measured |
| LMArena Document | 1403 | Not measured | Only GPT-5.1 measured |
| Neither model has a result on the other 8 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-5.1 | Inkling | 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
Inkling costs less
Repository review
50K input + 3K output tokens
Inkling costs less
Agent loop
200K input + 10K output tokens
Inkling 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 | Thinking Machines Inkling |
|---|---|---|
| Maker | OpenAI | Thinking Machines |
| Weights | No public weights listed | Open weights |
| Released | November 13, 2025 | July 17, 2026 |
| Context window | 400K | 524K |
| Input $/Mtok | $1.25 | $0.975 |
| Output $/Mtok | $10.00 | $4.05 |
| Coding index | 40.4 | 31.5 |
| Independent measurements behind it | 3 | 6 |
| Cost per solved task | $1.02 | $0.76 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5.1 better than Inkling for coding?
Pick GPT-5.1 for coding: it scores 40.4 on the Vibe Coding Index against 31.5 for Inkling, though on 3 benchmarks against 6. Pick Inkling for output tokens 2.5x cheaper ($4.05 vs $10.00 per million) and a lower cost per solved task ($0.76 against $1.02).
Which is cheaper, GPT-5.1 or Inkling?
GPT-5.1 costs $1.25 per million input tokens and $10.00 per million output tokens; Inkling costs $0.975 and $4.05. Per solved SWE-bench Verified task, GPT-5.1 costs $1.02 and Inkling $0.76.
Which has the bigger context window, GPT-5.1 or Inkling?
Inkling, with 524K tokens against 400K.
How many benchmarks is the GPT-5.1 vs Inkling comparison based on?
68 benchmarks have a result for both models as of October 21, 2026. GPT-5.1's coding index rests on 3 independent benchmarks and Inkling's on 6. Where only one model has a result, the page says so instead of naming a winner.