Claude Sonnet 4.5 vs Inkling 2 Small
Inkling 2 Small leads Claude Sonnet 4.5 on coding, 48.9 to 39.5 on the Vibe Coding Index, and Inkling 2 Small costs 15.0x less per output token ($1.00 vs $15.00 per million). Updated November 14, 2026; 25 benchmarks have a result for both.
Claude Sonnet 4.5 or Inkling 2 Small: which to pick
Pick Inkling 2 Small for coding: it scores 48.9 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5.
Pick Claude Sonnet 4.5 for work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.
- Shared results
- 25
- Claude Sonnet 4.5 only
- 75
- Inkling 2 Small only
- 26
- 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
Inkling 2 Small
Inkling 2 Small scores 48.9 against 39.5.
3 benchmarks behind each score
Intelligence
AA Intelligence Index
No call
Only Inkling 2 Small has a AA Intelligence Index result, 30.6.
Directional only
Agentic work
AA Agentic Index
No call
Only Claude Sonnet 4.5 has a AA Agentic Index result, 15.8.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Sonnet 4.5 has a GPQA Diamond result, 81.6%.
Directional only
Math
AIME
No call
Only Claude Sonnet 4.5 has a AIME result, 88.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Sonnet 4.5 has a MMLU Pro result, 87.4%.
Directional only
Web design
Design Arena: websites
No call
Only Claude Sonnet 4.5 has a Design Arena: websites result, 1181.
Directional only
General
Vals Index
No call
Only Inkling 2 Small has a Vals Index result, 56.1%.
Directional only
Long documents
Listed context window
Inkling 2 Small
Inkling 2 Small takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling 2 Small
Claude Sonnet 4.5 $0.011, Inkling 2 Small $0.0008 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Sonnet 4.5 has the number, $1.16.
Directional only
At a glance
- Coding index
- Claude Sonnet 4.5 39.5 from 3 benchmarks, Inkling 2 Small 48.9 from 3 benchmarks.
- Widest category
- Math, 29.3 points apart on average over 1 shared benchmark.
- Widest single gap
- ARC-AGI-2: Claude Sonnet 4.5 13.6% against Inkling 2 Small 81.7%, 68.1 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 4.5 $15.00 against Inkling 2 Small $1.00 per million output tokens, 15.0x apart.
- Context window
- Claude Sonnet 4.5 takes 1M tokens, Inkling 2 Small 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 | Claude Sonnet 4.5 | Bars | Inkling 2 Small | Ties |
|---|---|---|---|---|
| Coding | 2 | 4 | ||
| Agentic work | 0 | 1 | ||
| Reasoning | 3 | 2 | ||
| Math | 0 | 1 | ||
| Knowledge | 2 | 0 | ||
| General | 10 | 0 | ||
| All shared boards | 17 | 8 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index24
| Benchmark | Claude Sonnet 4.5 | Inkling 2 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 | 1393 | 1647 | Inkling 2 Small |
| AA Coding Index | 52.1 | Not measured | Only Claude Sonnet 4.5 measured |
| LiveCodeBench (Vals AI) | 73.0% | Not measured | Only Claude Sonnet 4.5 measured |
| SWE-bench Verified (Vals AI) | 70.0% | Not measured | Only Claude Sonnet 4.5 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 12.6% | Only Inkling 2 Small measured |
| Vibe Code Bench (Vals AI) | 22.6% | 81.5% | Inkling 2 Small |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only Inkling 2 Small measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 43.1% | Only Inkling 2 Small measured |
| CyberBench (Vals AI) | Not measured | 72.7% | Only Inkling 2 Small measured |
| SciCode | Not measured | 52.3% | Only Inkling 2 Small measured |
| Terminal-Bench 4.0 (Artificial Analysis run) | Not measured | 13.1% | Only Inkling 2 Small measured |
| FrontierCode 2.0 | Not measured | 25.4% | Only Inkling 2 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 | 1455 | Claude Sonnet 4.5 |
| LMArena Text: software and IT | 1473 | 1443 | Claude Sonnet 4.5 |
| LMArena WebDev: React | 1386 | 1660 | Inkling 2 Small |
| LMArena WebDev: HTML | 1398 | 1661 | Inkling 2 Small |
| SWE-Bench Pro V2 | Not measured | 97.7% | Only Inkling 2 Small measured |
| Terminal-Bench 2.0 | 46.5% | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 28 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Claude Sonnet 4.5 | Inkling 2 Small | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 30.6 | Only Inkling 2 Small measured |
| Epoch Capabilities Index | 147.6 | Not measured | Only Claude Sonnet 4.5 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Claude Sonnet 4.5 | Inkling 2 Small | Leader |
|---|---|---|---|
| AA Agentic Index | 15.8 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building web apps | 1036 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building full-stack apps | 1024 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building mobile apps | 1130 | Not measured | Only Claude Sonnet 4.5 measured |
| SREBench (Vals AI) | Not measured | 1.9% | Only Inkling 2 Small measured |
| Tax Agent Bench (Vals AI) | Not measured | 38.9% | Only Inkling 2 Small measured |
| Legal Research Bench (Vals AI) | Not measured | 46.6% | Only Inkling 2 Small measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 21.7% | Only Inkling 2 Small measured |
| BioMysteryBench (Vals AI) | Not measured | 70.0% | Only Inkling 2 Small measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 2.9% | Only Inkling 2 Small measured |
| Vals Science Index | Not measured | 32.7% | Only Inkling 2 Small measured |
| APEX-Agents | Not measured | 46.8% | Only Inkling 2 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 |
| LMArena Search | 1159 | Not measured | Only Claude Sonnet 4.5 measured |
| Berkeley Function Calling Leaderboard (BFCL) | 73.2% | Not measured | Only Claude Sonnet 4.5 measured |
| MCP Atlas | 59.5% | 85.4% | Inkling 2 Small |
| Neither model has a result on the other 23 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index32
| Benchmark | Claude Sonnet 4.5 | Inkling 2 Small | Leader |
|---|---|---|---|
| GPQA Diamond | 81.6% | Not measured | Only Claude Sonnet 4.5 measured |
| MysteryMechanism (Vals AI) | Not measured | 25.2% | Only Inkling 2 Small measured |
| MMMU Pro (Vals AI) | 79.3% | Not measured | Only Claude Sonnet 4.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 44.1% | Only Inkling 2 Small measured |
| HLE-Diamond (Artificial Analysis run) | Not measured | 28.7% | Only Inkling 2 Small measured |
| CritPt v2, hard subset (Artificial Analysis run) | Not measured | 35.0% | Only Inkling 2 Small measured |
| GPQA Diamond (Epoch AI run) | 82.3% | Not measured | Only Claude Sonnet 4.5 measured |
| ARC-AGI | 63.7% | 96.5% | Inkling 2 Small |
| ARC-AGI-2 | 13.6% | 81.7% | Inkling 2 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% | Not measured | Only Claude Sonnet 4.5 measured |
| 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 | 1421 | Claude Sonnet 4.5 |
| LMArena Text: expert | 1483 | 1478 | Claude Sonnet 4.5 |
| LMArena Text: hard prompts in English | 1471 | 1424 | Claude Sonnet 4.5 |
| Kagi LLM Benchmark | 57.9% | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 8 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Claude Sonnet 4.5 | Inkling 2 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% | Not measured | Only Claude Sonnet 4.5 measured |
| FrontierMath, tiers 1 to 3 | 23.9% | Not measured | Only Claude Sonnet 4.5 measured |
| FrontierMath, tier 4 | 2.4% | Not measured | Only Claude Sonnet 4.5 measured |
| ProofBench | 19.0% | Not measured | Only Claude Sonnet 4.5 measured |
| MATH level 5 | 97.7% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: math | 1449 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: mathematical work | 1463 | Not measured | Only Claude Sonnet 4.5 measured |
| MathArena | 13.2% | 42.4% | Inkling 2 Small |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 4.5 | Inkling 2 Small | Leader |
|---|---|---|---|
| MMLU Pro | 87.4% | Not measured | Only Claude Sonnet 4.5 measured |
| LegalBench (Vals AI) | 84.1% | Not measured | Only Claude Sonnet 4.5 measured |
| CaseLaw (Vals AI) | 62.2% | Not measured | Only Claude Sonnet 4.5 measured |
| CorpFin (Vals AI) | 62.0% | Not measured | Only Claude Sonnet 4.5 measured |
| TaxEval (Vals AI) | 73.3% | Not measured | Only Claude Sonnet 4.5 measured |
| MortgageTax (Vals AI) | 64.0% | Not measured | Only Claude Sonnet 4.5 measured |
| MedQA (Vals AI) | 94.7% | Not measured | Only Claude Sonnet 4.5 measured |
| MedCode (Vals AI) | 44.1% | Not measured | Only Claude Sonnet 4.5 measured |
| AA-Omniscience | Not measured | 16.1 | Only Inkling 2 Small measured |
| SimpleQA Verified | 30.7% | Not measured | Only Claude Sonnet 4.5 measured |
| GeoBench | 60.0% | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: science | 1447 | 1409 | Claude Sonnet 4.5 |
| LMArena Text: medicine and healthcare | 1443 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: legal and government | 1450 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: business and finance | 1440 | 1415 | Claude Sonnet 4.5 |
| PRBench Finance | 43.8% | Not measured | Only Claude Sonnet 4.5 measured |
| PRBench Legal | 40.8% | 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 2 Small | Leader |
|---|---|---|---|
| Design Arena: websites | 1181 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: UI components | 1162 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: game dev | 1155 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: data viz | 1164 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: 3D | 1137 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: all code categories | 1172 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: SVG | 1104 | Not measured | Only Claude Sonnet 4.5 measured |
| Design Arena: ASCII art | 1200 | 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 index100
| Benchmark | Claude Sonnet 4.5 | Inkling 2 Small | Leader |
|---|---|---|---|
| Vals Index | Not measured | 56.1% | Only Inkling 2 Small measured |
| SAGE (Vals AI) | Not measured | 88.6% | Only Inkling 2 Small measured |
| MedScribe (Vals AI) | 84.5% | Not measured | Only Claude Sonnet 4.5 measured |
| Long context reasoning (AA-LCR) | Not measured | 83.3% | Only Inkling 2 Small measured |
| GDPval-AA | Not measured | 1630 | Only Inkling 2 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 | 1439 | 1403 | Claude Sonnet 4.5 |
| LMArena Text: instruction following | 1459 | 1408 | Claude Sonnet 4.5 |
| LMArena Text: creative writing | 1442 | 1348 | Claude Sonnet 4.5 |
| LMArena Text: English | 1450 | 1418 | Claude Sonnet 4.5 |
| LMArena Text: non-English | 1425 | 1390 | Claude Sonnet 4.5 |
| LMArena Text: Chinese | 1461 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: German | 1427 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Japanese | 1389 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Korean | 1400 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: French | 1459 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Spanish | 1457 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: Russian | 1437 | 1377 | Claude Sonnet 4.5 |
| LMArena Text: Polish | 1423 | Not measured | Only Claude Sonnet 4.5 measured |
| LMArena Text: multi-turn | 1465 | 1408 | Claude Sonnet 4.5 |
| LMArena Text: longer queries | 1476 | 1403 | Claude Sonnet 4.5 |
| LMArena Text: writing and language | 1442 | 1381 | Claude Sonnet 4.5 |
| LMArena Text: entertainment and media | 1429 | 1359 | Claude Sonnet 4.5 |
| LMArena Document | 1449 | Not measured | Only Claude Sonnet 4.5 measured |
| MultiChallenge | 55.3% | Not measured | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 23 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 4.5 | Inkling 2 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 2 Small costs less
Repository review
50K input + 3K output tokens
Inkling 2 Small costs less
Agent loop
200K input + 10K output tokens
Inkling 2 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 2 Small |
|---|---|---|
| Maker | Anthropic | Thinking Machines |
| Weights | No public weights listed | Open weights |
| Released | September 29, 2025 | November 9, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $3.00 | $0.30 |
| Output $/Mtok | $15.00 | $1.00 |
| Coding index | 39.5 | 48.9 |
| Independent measurements behind it | 3 | 3 |
| Cost per solved task | $1.16 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 4.5 better than Inkling 2 Small for coding?
Pick Inkling 2 Small for coding: it scores 48.9 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5. Pick Claude Sonnet 4.5 for work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.
Which is cheaper, Claude Sonnet 4.5 or Inkling 2 Small?
Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; Inkling 2 Small costs $0.30 and $1.00. Cost per solved task is known for Claude Sonnet 4.5 only.
Which has the bigger context window, Claude Sonnet 4.5 or Inkling 2 Small?
Inkling 2 Small, with 1.05M tokens against 1M.
How many benchmarks is the Claude Sonnet 4.5 vs Inkling 2 Small comparison based on?
25 benchmarks have a result for both models as of November 14, 2026. Claude Sonnet 4.5's coding index rests on 3 independent benchmarks and Inkling 2 Small's on 3. Where only one model has a result, the page says so instead of naming a winner.