Step 3.5 Flash vs Inkling Small
Updated October 21, 2026. 32 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Only Inkling Small has a coding score, 27.3 on the Vibe Coding Index; Step 3.5 Flash has none, so the two cannot be ranked on coding.
Step 3.5 Flash has the edge where output tokens cost 4.0x less, and where what matters is LMArena Text: creative writing or LMArena Text: writing and language, where it leads.
- Shared results
- 32
- Step 3.5 Flash only
- 3
- Inkling Small only
- 52
- Like-for-like categories
- 6 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, six public coding benchmarks
No call
Only Inkling Small has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Inkling Small
Inkling Small leads, 25.7 against 17.0.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Inkling Small has a AA Agentic Index result, 23.5.
Directional only
Reasoning
GPQA Diamond
No call
Only Inkling Small has a GPQA Diamond result, 83.6%.
Directional only
Knowledge
MMLU Pro
No call
Only Inkling Small has a MMLU Pro result, 85.6%.
Directional only
General
Vals Index
No call
Only Inkling Small has a Vals Index result, 27.6%.
Directional only
Long documents
Listed context window
Inkling Small
Inkling Small takes 524K tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Step 3.5 Flash
Step 3.5 Flash $0.0003, Inkling Small $0.0010 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Inkling Small has the number, $0.16.
Directional only
At a glance
- Coding index
- Step 3.5 Flash not benchmarked, Inkling Small 27.3 from 4 benchmarks.
- Widest category
- Intelligence, 8.7 points apart on average over 1 shared benchmark.
- Widest single gap
- Long context reasoning (AA-LCR): Step 3.5 Flash 63.0% against Inkling Small 75.7%, 12.7 points apart on a 0 to 100 scale.
- Output price
- Step 3.5 Flash $0.30 against Inkling Small $1.20 per million output tokens, 4.0x apart.
- Context window
- Step 3.5 Flash takes 262K 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 | Step 3.5 Flash | Bars | Inkling Small | Ties |
|---|---|---|---|---|
| Coding | 0 | 2 | ||
| Intelligence | 0 | 1 | ||
| Reasoning | 0 | 5 | ||
| Math | 0 | 2 | ||
| Knowledge | 0 | 4 | ||
| General | 3 | 15 | ||
| All shared boards | 3 | 29 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index02
| Benchmark | Step 3.5 Flash | Inkling Small | Leader |
|---|---|---|---|
| LMArena WebDev | Not measured | 1409 | Only Inkling Small measured |
| AA Coding Index | Not measured | 52.9 | Only Inkling Small measured |
| LiveCodeBench (Vals AI) | Not measured | 85.9% | Only Inkling Small measured |
| SWE-bench Verified (Vals AI) | Not measured | 82.2% | Only Inkling Small measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 0.0% | Only Inkling Small measured |
| Vibe Code Bench (Vals AI) | Not measured | 19.1% | Only Inkling Small measured |
| 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 Hard (Artificial Analysis run) | 32.6% | Not measured | Only Step 3.5 Flash measured |
| LMArena Text: coding | 1436 | 1450 | Inkling Small |
| LMArena Text: software and IT | 1434 | 1447 | Inkling Small |
| LMArena WebDev: React | Not measured | 1399 | Only Inkling Small measured |
| LMArena WebDev: HTML | Not measured | 1398 | Only Inkling Small measured |
| LMArena WebDev: from an image | Not measured | 1410 | Only Inkling Small measured |
| Neither model has a result on the other 19 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Step 3.5 Flash | Inkling Small | Leader |
|---|---|---|---|
| AA Intelligence Index | 17.0 | 25.7 | Inkling Small |
| Epoch Capabilities Index | Not measured | 150.3 | Only Inkling Small measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Step 3.5 Flash | Inkling Small | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 23.5 | Only Inkling Small 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 |
| τ²-Bench Telecom | 94.4% | Not measured | Only Step 3.5 Flash measured |
| Neither model has a result on the other 32 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | Step 3.5 Flash | Inkling Small | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 83.6% | Only Inkling Small measured |
| GPQA Diamond (Artificial Analysis run) | 83.1% | 89.5% | Inkling Small |
| Humanity's Last Exam (Artificial Analysis run) | 24.5% | 33.3% | Inkling Small |
| GPQA Diamond (Epoch AI run) | Not measured | 88.5% | Only Inkling Small measured |
| ARC-AGI | Not measured | 84.0% | Only Inkling Small measured |
| ARC-AGI-2 | Not measured | 40.1% | Only Inkling Small measured |
| Mystery game puzzles | Not measured | 6.0% | Only Inkling Small measured |
| LMArena Text: hard prompts | 1411 | 1423 | Inkling Small |
| LMArena Text: expert | 1421 | 1441 | Inkling Small |
| LMArena Text: hard prompts in English | 1421 | 1429 | Inkling Small |
| LMArena Vision: diagrams | Not measured | 1251 | Only Inkling Small measured |
| LMArena Vision: homework | Not measured | 1257 | Only Inkling Small measured |
| Neither model has a result on the other 9 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Step 3.5 Flash | Inkling Small | Leader |
|---|---|---|---|
| OTIS Mock AIME | Not measured | 90.0% | Only Inkling Small measured |
| FrontierMath, tiers 1 to 3 | Not measured | 46.3% | Only Inkling Small measured |
| FrontierMath, tier 4 | Not measured | 17.1% | Only Inkling Small measured |
| ProofBench | Not measured | 6.0% | Only Inkling Small measured |
| LMArena Text: math | 1408 | 1459 | Inkling Small |
| LMArena Text: mathematical work | 1421 | 1441 | Inkling Small |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | Step 3.5 Flash | Inkling Small | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 85.6% | Only Inkling Small measured |
| LegalBench (Vals AI) | Not measured | 83.0% | Only Inkling Small measured |
| CorpFin (Vals AI) | Not measured | 69.6% | Only Inkling Small measured |
| TaxEval (Vals AI) | Not measured | 75.5% | Only Inkling Small measured |
| MortgageTax (Vals AI) | Not measured | 62.3% | Only Inkling Small measured |
| MedCode (Vals AI) | Not measured | 37.9% | Only Inkling Small measured |
| SimpleQA Verified | Not measured | 19.1% | Only Inkling Small measured |
| LMArena Text: science | 1415 | 1428 | Inkling Small |
| LMArena Text: medicine and healthcare | 1408 | 1413 | Inkling Small |
| LMArena Text: legal and government | 1408 | 1415 | Inkling Small |
| LMArena Text: business and finance | 1394 | 1413 | Inkling Small |
| Neither model has a result on the other 6 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Step 3.5 Flash | Inkling Small | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index315
| Benchmark | Step 3.5 Flash | 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) | Not measured | 32.7% | Only Inkling Small measured |
| MedScribe (Vals AI) | Not measured | 84.1% | Only Inkling Small measured |
| Vals Multimodal Index | Not measured | 50.0% | Only Inkling Small measured |
| IFBench | 66.5% | Not measured | Only Step 3.5 Flash measured |
| Long context reasoning (AA-LCR) | 63.0% | 75.7% | Inkling Small |
| LMArena Text | 1403 | 1413 | Inkling Small |
| LMArena Text: instruction following | 1385 | 1399 | Inkling Small |
| LMArena Text: creative writing | 1357 | 1334 | Step 3.5 Flash |
| LMArena Vision | Not measured | 1237 | Only Inkling Small measured |
| LMArena Text: English | 1417 | 1421 | Inkling Small |
| LMArena Text: non-English | 1385 | 1401 | Inkling Small |
| LMArena Text: Chinese | 1446 | 1464 | Inkling Small |
| LMArena Text: German | 1405 | 1408 | Inkling Small |
| LMArena Text: Japanese | 1353 | 1401 | Inkling Small |
| LMArena Text: Korean | 1351 | 1367 | Inkling Small |
| LMArena Text: French | 1421 | 1435 | Inkling Small |
| LMArena Text: Spanish | 1419 | 1422 | Inkling Small |
| LMArena Text: Russian | 1385 | 1394 | Inkling Small |
| LMArena Text: Polish | 1389 | 1428 | Inkling Small |
| LMArena Text: multi-turn | 1404 | 1416 | Inkling Small |
| LMArena Text: longer queries | 1402 | 1402 | Inkling Small |
| LMArena Text: writing and language | 1372 | 1357 | Step 3.5 Flash |
| LMArena Text: entertainment and media | 1360 | 1352 | Step 3.5 Flash |
| 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 |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Step 3.5 Flash | 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
Step 3.5 Flash costs less
Repository review
50K input + 3K output tokens
Step 3.5 Flash costs less
Agent loop
200K input + 10K output tokens
Step 3.5 Flash 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 | StepFun Step 3.5 Flash | Thinking Machines Inkling Small |
|---|---|---|
| Maker | StepFun | Thinking Machines |
| Weights | Open weights | Open weights |
| Released | January 29, 2026 | July 30, 2026 |
| Context window | 262K | 524K |
| Input $/Mtok | $0.10 | $0.45 |
| Output $/Mtok | $0.30 | $1.20 |
| Coding index | Not benchmarked | 27.3 |
| Independent measurements behind it | 0 | 4 |
| Cost per solved task | Not computable | $0.16 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Step 3.5 Flash better than Inkling Small for coding?
Only Inkling Small has a coding score, 27.3 on the Vibe Coding Index; Step 3.5 Flash has none, so the two cannot be ranked on coding. Step 3.5 Flash has the edge where output tokens cost 4.0x less, and where what matters is LMArena Text: creative writing or LMArena Text: writing and language, where it leads.
Which is cheaper, Step 3.5 Flash or Inkling Small?
Step 3.5 Flash costs $0.10 per million input tokens and $0.30 per million output tokens; Inkling Small costs $0.45 and $1.20. Cost per solved task is known for Inkling Small only.
Which has the bigger context window, Step 3.5 Flash or Inkling Small?
Inkling Small, with 524K tokens against 262K.
How many benchmarks is the Step 3.5 Flash vs Inkling Small comparison based on?
32 benchmarks have a result for both models as of October 21, 2026. Step 3.5 Flash's coding index rests on 0 independent benchmarks and Inkling Small's on 4. Where only one model has a result, the page says so instead of naming a winner.