Claude Sonnet 4.5 vs Inkling Small
Claude Sonnet 4.5 leads Inkling Small on coding, 39.5 to 27.3 on the Vibe Coding Index, and Inkling Small costs 12.5x less per output token ($1.20 vs $15.00 per million). Updated October 22, 2026; 56 benchmarks have a result for both.
Claude Sonnet 4.5 or Inkling Small: which to pick
Pick Claude Sonnet 4.5 for coding: it scores 39.5 on the Vibe Coding Index against 27.3 for Inkling Small, though on 3 benchmarks against 4.
Pick Inkling Small for output tokens 12.5x cheaper ($1.20 vs $15.00 per million) and a lower cost per solved task ($0.16 against $1.16).
- Shared results
- 56
- Claude Sonnet 4.5 only
- 39
- Inkling Small only
- 28
- 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
Claude Sonnet 4.5
Claude Sonnet 4.5 scores 39.5 against 27.3.
3 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Inkling Small
Inkling Small leads, 25.7 against 20.7.
Same board, both measured
Agentic work
AA Agentic Index
Inkling Small
Inkling Small leads, 23.5 against 15.8.
Same board, both measured
Reasoning
GPQA Diamond
Inkling Small
Inkling Small leads, 83.6% against 81.6%.
Same board, both measured
Math
AIME
No call
Only Claude Sonnet 4.5 has a AIME result, 88.2%.
Directional only
Knowledge
MMLU Pro
Claude Sonnet 4.5
Claude Sonnet 4.5 leads, 87.4% against 85.6%.
Same board, both measured
Web design
Design Arena: websites
No call
Only Claude Sonnet 4.5 has a Design Arena: websites result, 1189.
Directional only
General
Vals Index
No call
Only Inkling Small has a Vals Index result, 27.6%.
Directional only
Long documents
Listed context window
Claude Sonnet 4.5
Claude Sonnet 4.5 takes 1M tokens against 524K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling Small
Claude Sonnet 4.5 $0.011, Inkling Small $0.0010 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Inkling Small
Claude Sonnet 4.5 $1.16, Inkling Small $0.16.
Published attempt cost and pass rate
At a glance
- Coding index
- Claude Sonnet 4.5 39.5 from 3 benchmarks, Inkling Small 27.3 from 4 benchmarks.
- Widest category
- Math, 11.3 points apart on average over 6 shared benchmarks.
- Widest single gap
- ARC-AGI-2: Claude Sonnet 4.5 13.6% against Inkling Small 40.1%, 26.5 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 4.5 $15.00 against Inkling Small $1.20 per million output tokens, 12.5x apart.
- Context window
- Claude Sonnet 4.5 takes 1M tokens, Inkling Small 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 | Claude Sonnet 4.5 | Bars | Inkling Small | Ties |
|---|---|---|---|---|
| Coding | 4 | 5 | ||
| Intelligence | 0 | 2 | ||
| Agentic work | 0 | 1 | ||
| Reasoning | 4 | 4 | ||
| Math | 2 | 4 | ||
| Knowledge | 9 | 2 | ||
| General | 16 | 3 | ||
| All shared boards | 35 | 21 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index45
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| SWE-bench Verified | 74.8% | Not measured | Only Claude Sonnet 4.5 measured |
| SWE-bench Multilingual | 67.0% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena WebDev | 1394 | 1409 | Inkling Small |
| AA Coding Index | 52.1 | 52.9 | Inkling Small |
| LiveCodeBench (Vals AI) | 73.0% | 85.9% | Inkling Small |
| SWE-bench Verified (Vals AI) | 70.0% | 82.2% | Inkling Small |
| Terminal-Bench 4 (Vals AI) | Not measured | 0.0% | Only Inkling Small measured |
| Vibe Code Bench (Vals AI) | 22.6% | 19.1% | Claude Sonnet 4.5 |
| Code migration (Vals AI) | Not measured | 13.7% | Only Inkling Small measured |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only Inkling Small measured |
| IOI (Vals AI) | Not measured | 9.3% | Only Inkling Small measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 55.1% | Only Inkling Small measured |
| SkillsBench (Vals AI) | Not measured | 33.6% | Only Inkling Small measured |
| CyberBench (Vals AI) | Not measured | 64.1% | Only Inkling Small measured |
| SciCode | Not measured | 49.7% | Only Inkling Small measured |
| Terminal-Bench | 46.5% | Not measured | Only Claude Sonnet 4.5 measured |
| GSO-Bench | 14.7% | Not measured | Only Claude Sonnet 4.5 measured |
| WeirdML | 47.7% | Not measured | Only Claude Sonnet 4.5 measured |
| Cybench | 60.0% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: coding | 1488 | 1450 | Claude Sonnet 4.5 |
| LMArena Text: software and IT | 1473 | 1447 | Claude Sonnet 4.5 |
| LMArena WebDev: React | 1386 | 1399 | Inkling Small |
| LMArena WebDev: HTML | 1399 | 1398 | Claude Sonnet 4.5 |
| LMArena WebDev: from an image | Not measured | 1410 | Only Inkling Small measured |
| Neither model has a result on the other 15 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| AA Intelligence Index | 20.7 | 25.7 | Inkling Small |
| Epoch Capabilities Index | 146.7 | 150.3 | Inkling Small |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| AA Agentic Index | 15.8 | 23.5 | Inkling Small |
| Design Arena: agents building web apps | 1060 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building full-stack apps | 1050 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building mobile apps | 1137 | Not measured | Only Claude Sonnet 4.5 measured |
| Finance Agent (Vals AI) | Not measured | 41.3% | Only Inkling Small measured |
| Tax Agent Bench (Vals AI) | Not measured | 15.4% | Only Inkling Small measured |
| Legal Research Bench (Vals AI) | Not measured | 25.5% | Only Inkling Small measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 2.9% | Only Inkling Small measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 31.8% | Only Inkling Small measured |
| METR time horizons | 67.4% | Not measured | Only Claude Sonnet 4.5 measured |
| Remote Labor Index | 2.1% | Not measured | Only Claude Sonnet 4.5 measured |
| GDPval | 42.5% | Not measured | Only Claude Sonnet 4.5 measured |
| DeepResearch Bench | 52.6% | Not measured | Only Claude Sonnet 4.5 measured |
| OSWorld | 62.9% | Not measured | Only Claude Sonnet 4.5 measured |
| Vending-Bench 2 | $3,839 | Not measured | Only Claude Sonnet 4.5 measured |
| Berkeley Function Calling Leaderboard (BFCL) | 73.2% | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 25 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index44
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| GPQA Diamond | 81.6% | 83.6% | Inkling Small |
| MMMU Pro (Vals AI) | 79.3% | Not measured | Only Claude Sonnet 4.5 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 89.5% | Only Inkling Small measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 33.3% | Only Inkling Small measured |
| GPQA Diamond (Epoch AI run) | 82.3% | 88.5% | Inkling Small |
| ARC-AGI | 63.7% | 84.0% | Inkling Small |
| ARC-AGI-2 | 13.6% | 40.1% | Inkling Small |
| SimpleBench | 54.3% | Not measured | Only Claude Sonnet 4.5 measured |
| Chess puzzles | 10.0% | Not measured | Only Claude Sonnet 4.5 measured |
| Mystery game puzzles | 17.0% | 6.0% | Claude Sonnet 4.5 |
| EBR-bench | 2.4% | Not measured | Only Claude Sonnet 4.5 measured |
| VPCT | 39.8% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts | 1462 | 1423 | Claude Sonnet 4.5 |
| LMArena Text: expert | 1483 | 1441 | Claude Sonnet 4.5 |
| LMArena Text: hard prompts in English | 1471 | 1429 | Claude Sonnet 4.5 |
| LMArena Vision: diagrams | Not measured | 1251 | Only Inkling Small measured |
| LMArena Vision: homework | Not measured | 1257 | Only Inkling Small measured |
| Kagi LLM Benchmark | 57.9% | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index24
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| AIME | 88.2% | Not measured | Only Claude Sonnet 4.5 measured |
| MGSM (Vals AI) | 94.3% | Not measured | Only Claude Sonnet 4.5 measured |
| OTIS Mock AIME | 77.8% | 90.0% | Inkling Small |
| FrontierMath, tiers 1 to 3 | 23.9% | 46.3% | Inkling Small |
| FrontierMath, tier 4 | 2.4% | 17.1% | Inkling Small |
| ProofBench | 19.0% | 6.0% | Claude Sonnet 4.5 |
| MATH level 5 | 97.7% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: math | 1449 | 1459 | Inkling Small |
| LMArena Text: mathematical work | 1462 | 1441 | Claude Sonnet 4.5 |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index92
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| MMLU Pro | 87.4% | 85.6% | Claude Sonnet 4.5 |
| LegalBench (Vals AI) | 84.1% | 83.0% | Claude Sonnet 4.5 |
| CaseLaw (Vals AI) | 62.2% | Not measured | Only Claude Sonnet 4.5 measured |
| CorpFin (Vals AI) | 62.0% | 69.6% | Inkling Small |
| TaxEval (Vals AI) | 73.3% | 75.5% | Inkling Small |
| MortgageTax (Vals AI) | 64.0% | 62.3% | Claude Sonnet 4.5 |
| MedQA (Vals AI) | 94.7% | Not measured | Only Claude Sonnet 4.5 measured |
| MedCode (Vals AI) | 44.1% | 37.9% | Claude Sonnet 4.5 |
| SimpleQA Verified | 30.7% | 19.1% | Claude Sonnet 4.5 |
| LMArena Text: science | 1448 | 1428 | Claude Sonnet 4.5 |
| LMArena Text: medicine and healthcare | 1444 | 1413 | Claude Sonnet 4.5 |
| LMArena Text: legal and government | 1451 | 1415 | Claude Sonnet 4.5 |
| LMArena Text: business and finance | 1440 | 1413 | Claude Sonnet 4.5 |
| FACTS Benchmark Suite | 40.6% | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 4 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| Design Arena: websites | 1189 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: UI components | 1170 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: game dev | 1166 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: data viz | 1167 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: 3D | 1157 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: all code categories | 1182 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: SVG | 1115 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: ASCII art | 1205 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index163
| Benchmark | Claude Sonnet 4.5 | Inkling Small | Leader |
|---|---|---|---|
| Vals Index | Not measured | 27.6% | Only Inkling Small measured |
| Public Benefits Bench (Vals AI) | Not measured | 59.4% | Only Inkling Small measured |
| SAGE (Vals AI) | 36.1% | 32.7% | Claude Sonnet 4.5 |
| MedScribe (Vals AI) | 84.5% | 84.1% | Claude Sonnet 4.5 |
| Vals Multimodal Index | Not measured | 50.0% | Only Inkling Small measured |
| Long context reasoning (AA-LCR) | Not measured | 75.7% | Only Inkling Small measured |
| DTBench | 83.2% | Not measured | Only Claude Sonnet 4.5 measured |
| LMCA | 38.8% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text | 1438 | 1413 | Claude Sonnet 4.5 |
| LMArena Text: instruction following | 1459 | 1399 | Claude Sonnet 4.5 |
| LMArena Text: creative writing | 1442 | 1334 | Claude Sonnet 4.5 |
| LMArena Vision | Not measured | 1237 | Only Inkling Small measured |
| LMArena Text: English | 1450 | 1421 | Claude Sonnet 4.5 |
| LMArena Text: non-English | 1425 | 1401 | Claude Sonnet 4.5 |
| LMArena Text: Chinese | 1460 | 1464 | Inkling Small |
| LMArena Text: German | 1427 | 1408 | Claude Sonnet 4.5 |
| LMArena Text: Japanese | 1390 | 1401 | Inkling Small |
| LMArena Text: Korean | 1402 | 1367 | Claude Sonnet 4.5 |
| LMArena Text: French | 1459 | 1435 | Claude Sonnet 4.5 |
| LMArena Text: Spanish | 1458 | 1422 | Claude Sonnet 4.5 |
| LMArena Text: Russian | 1437 | 1394 | Claude Sonnet 4.5 |
| LMArena Text: Polish | 1423 | 1428 | Inkling Small |
| LMArena Text: multi-turn | 1465 | 1416 | Claude Sonnet 4.5 |
| LMArena Text: longer queries | 1475 | 1402 | Claude Sonnet 4.5 |
| LMArena Text: writing and language | 1442 | 1357 | Claude Sonnet 4.5 |
| LMArena Text: entertainment and media | 1428 | 1352 | Claude Sonnet 4.5 |
| LMArena Vision: English | Not measured | 1243 | Only Inkling Small measured |
| LMArena Vision: Chinese | Not measured | 1292 | Only Inkling Small measured |
| LMArena Vision: reading text | Not measured | 1243 | Only Inkling Small measured |
| LMArena Vision: humor | Not measured | 1207 | Only Inkling Small measured |
| LMArena Vision: creative writing | Not measured | 1205 | Only Inkling Small measured |
| LMArena Document | 1450 | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 14 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 4.5 | Inkling Small | 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 Small costs less
Repository review
50K input + 3K output tokens
Inkling Small costs less
Agent loop
200K input + 10K output tokens
Inkling Small 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 | Anthropic Claude Sonnet 4.5 | Thinking Machines Inkling Small |
|---|---|---|
| Maker | Anthropic | Thinking Machines |
| Weights | No public weights listed | Open weights |
| Released | September 29, 2025 | July 30, 2026 |
| Context window | 1M | 524K |
| Input $/Mtok | $3.00 | $0.45 |
| Output $/Mtok | $15.00 | $1.20 |
| Coding index | 39.5 | 27.3 |
| Independent measurements behind it | 3 | 4 |
| Cost per solved task | $1.16 | $0.16 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 4.5 better than Inkling Small for coding?
Pick Claude Sonnet 4.5 for coding: it scores 39.5 on the Vibe Coding Index against 27.3 for Inkling Small, though on 3 benchmarks against 4. Pick Inkling Small for output tokens 12.5x cheaper ($1.20 vs $15.00 per million) and a lower cost per solved task ($0.16 against $1.16).
Which is cheaper, Claude Sonnet 4.5 or Inkling Small?
Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; Inkling Small costs $0.45 and $1.20. Per solved SWE-bench Verified task, Claude Sonnet 4.5 costs $1.16 and Inkling Small $0.16.
Which has the bigger context window, Claude Sonnet 4.5 or Inkling Small?
Claude Sonnet 4.5, with 1M tokens against 524K.
How many benchmarks is the Claude Sonnet 4.5 vs Inkling Small comparison based on?
56 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 4.5's coding index rests on 3 independent benchmarks and Inkling Small's on 4. Where only one model has a result, the page says so instead of naming a winner.