Step 5 Preview vs Inkling Small
Step 5 Preview leads Inkling Small on coding, 61.1 to 27.3 on the Vibe Coding Index, and Inkling Small costs 2.3x less per output token ($1.20 vs $2.70 per million). Updated October 22, 2026; 48 benchmarks have a result for both.
Step 5 Preview or Inkling Small: which to pick
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 27.3 for Inkling Small.
Pick Inkling Small for output tokens 2.3x cheaper ($1.20 vs $2.70 per million) and work measured by LMArena Text: math or Public Benefits Bench (Vals AI), where it leads.
- Shared results
- 48
- Step 5 Preview only
- 13
- Inkling Small only
- 36
- 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
Step 5 Preview
Step 5 Preview scores 61.1 against 27.3.
4 benchmarks behind each score
Intelligence
AA Intelligence Index
Step 5 Preview
Step 5 Preview leads, 43.7 against 25.7.
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
Step 5 Preview
Step 5 Preview takes 1.05M tokens against 524K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling Small
Step 5 Preview $0.0024, 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 5 Preview 61.1 from 4 benchmarks, Inkling Small 27.3 from 4 benchmarks.
- Widest category
- Coding, 24.5 points apart on average over 11 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): Step 5 Preview 70.4% against Inkling Small 19.1%, 51.4 points apart on a 0 to 100 scale.
- Output price
- Step 5 Preview $2.70 against Inkling Small $1.20 per million output tokens, 2.3x apart.
- Context window
- Step 5 Preview takes 1.05M 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 5 Preview | Bars | Inkling Small | Ties |
|---|---|---|---|---|
| Coding | 11 | 0 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 4 | 0 | ||
| Reasoning | 6 | 0 | ||
| Math | 2 | 1 | ||
| Knowledge | 4 | 0 | ||
| General | 17 | 2 | ||
| All shared boards | 45 | 3 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index110
| Benchmark | Step 5 Preview | Inkling Small | Leader |
|---|---|---|---|
| LiveBench coding | 85.6% | Not measured | Only Step 5 Preview measured |
| LMArena WebDev | 1567 | 1409 | Step 5 Preview |
| 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) | 31.8% | 0.0% | Step 5 Preview |
| Vibe Code Bench (Vals AI) | 70.4% | 19.1% | Step 5 Preview |
| Code migration (Vals AI) | 39.0% | 13.7% | Step 5 Preview |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only Inkling Small measured |
| IOI (Vals AI) | 38.1% | 9.3% | Step 5 Preview |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 55.1% | Only Inkling Small measured |
| SWE-bench Multimodal (Vals AI) | 40.8% | Not measured | Only Step 5 Preview measured |
| SkillsBench (Vals AI) | Not measured | 33.6% | Only Inkling Small measured |
| CyberBench (Vals AI) | Not measured | 64.1% | Only Inkling Small measured |
| SciCode | 58.9% | 49.7% | Step 5 Preview |
| LMArena Text: coding | 1485 | 1450 | Step 5 Preview |
| LMArena Text: software and IT | 1473 | 1447 | Step 5 Preview |
| LMArena WebDev: React | 1583 | 1399 | Step 5 Preview |
| LMArena WebDev: HTML | 1556 | 1398 | Step 5 Preview |
| LMArena WebDev: from an image | 1550 | 1410 | Step 5 Preview |
| Neither model has a result on the other 19 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Step 5 Preview | Inkling Small | Leader |
|---|---|---|---|
| AA Intelligence Index | 43.7 | 25.7 | Step 5 Preview |
| Epoch Capabilities Index | Not measured | 150.3 | Only Inkling Small measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Step 5 Preview | Inkling Small | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 23.5 | Only Inkling Small measured |
| LiveBench research | 72.8% | Not measured | Only Step 5 Preview measured |
| LiveBench browser | 24.0% | Not measured | Only Step 5 Preview measured |
| LiveBench long agentic | 27.5% | Not measured | Only Step 5 Preview measured |
| SREBench (Vals AI) | 0.4% | Not measured | Only Step 5 Preview measured |
| Finance Agent (Vals AI) | 50.7% | 41.3% | Step 5 Preview |
| Tax Agent Bench (Vals AI) | 27.3% | 15.4% | Step 5 Preview |
| Legal Research Bench (Vals AI) | 40.4% | 25.5% | Step 5 Preview |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 2.9% | Only Inkling Small measured |
| Excel Modeling Benchmark (Vals AI) | 57.1% | 31.8% | Step 5 Preview |
| BioMysteryBench (Vals AI) | 67.4% | Not measured | Only Step 5 Preview measured |
| Terminal-Bench-Science (Vals AI) | 2.9% | Not measured | Only Step 5 Preview measured |
| Vals Science Index | 29.6% | Not measured | Only Step 5 Preview measured |
| Neither model has a result on the other 28 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Step 5 Preview | Inkling Small | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 83.6% | Only Inkling Small measured |
| LiveBench reasoning | 83.8% | Not measured | Only Step 5 Preview measured |
| MysteryMechanism (Vals AI) | 18.5% | Not measured | Only Step 5 Preview measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 89.5% | Only Inkling Small measured |
| Humanity's Last Exam (Artificial Analysis run) | 46.5% | 33.3% | Step 5 Preview |
| 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 | 1461 | 1423 | Step 5 Preview |
| LMArena Text: expert | 1485 | 1441 | Step 5 Preview |
| LMArena Text: hard prompts in English | 1454 | 1429 | Step 5 Preview |
| LMArena Vision: diagrams | 1308 | 1251 | Step 5 Preview |
| LMArena Vision: homework | 1265 | 1257 | Step 5 Preview |
| Neither model has a result on the other 8 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index21
| Benchmark | Step 5 Preview | 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 | 42.0% | 6.0% | Step 5 Preview |
| LMArena Text: math | 1458 | 1459 | Inkling Small |
| LMArena Text: mathematical work | 1460 | 1441 | Step 5 Preview |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Step 5 Preview | 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 | 1454 | 1428 | Step 5 Preview |
| LMArena Text: medicine and healthcare | 1439 | 1413 | Step 5 Preview |
| LMArena Text: legal and government | 1437 | 1415 | Step 5 Preview |
| LMArena Text: business and finance | 1435 | 1413 | Step 5 Preview |
| Neither model has a result on the other 7 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Step 5 Preview | Inkling Small | Leader |
|---|---|---|---|
| LiveBench design | 76.9% | Not measured | Only Step 5 Preview measured |
| Neither model has a result on the other 8 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index172
| Benchmark | Step 5 Preview | Inkling Small | Leader |
|---|---|---|---|
| Vals Index | Not measured | 27.6% | Only Inkling Small measured |
| LiveBench data analysis | 63.5% | Not measured | Only Step 5 Preview measured |
| Public Benefits Bench (Vals AI) | 58.1% | 59.4% | Inkling Small |
| 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 |
| Long context reasoning (AA-LCR) | 88.3% | 75.7% | Step 5 Preview |
| LMArena Text | 1440 | 1413 | Step 5 Preview |
| LMArena Text: instruction following | 1438 | 1399 | Step 5 Preview |
| LMArena Text: creative writing | 1409 | 1334 | Step 5 Preview |
| LMArena Vision | 1265 | 1237 | Step 5 Preview |
| LMArena Text: English | 1447 | 1421 | Step 5 Preview |
| LMArena Text: non-English | 1428 | 1401 | Step 5 Preview |
| LMArena Text: Chinese | 1500 | 1464 | Step 5 Preview |
| LMArena Text: German | Not measured | 1408 | Only Inkling Small measured |
| LMArena Text: Japanese | 1383 | 1401 | Inkling Small |
| LMArena Text: Korean | Not measured | 1367 | Only Inkling Small measured |
| LMArena Text: French | 1438 | 1435 | Step 5 Preview |
| LMArena Text: Spanish | 1441 | 1422 | Step 5 Preview |
| LMArena Text: Russian | 1433 | 1394 | Step 5 Preview |
| LMArena Text: Polish | Not measured | 1428 | Only Inkling Small measured |
| LMArena Text: multi-turn | 1437 | 1416 | Step 5 Preview |
| LMArena Text: longer queries | 1449 | 1402 | Step 5 Preview |
| LMArena Text: writing and language | 1425 | 1357 | Step 5 Preview |
| LMArena Text: entertainment and media | 1412 | 1352 | Step 5 Preview |
| LMArena Vision: English | 1290 | 1243 | Step 5 Preview |
| LMArena Vision: Chinese | Not measured | 1292 | Only Inkling Small measured |
| LMArena Vision: reading text | 1282 | 1243 | Step 5 Preview |
| 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 5 Preview | 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 | StepFun Step 5 Preview | Thinking Machines Inkling Small |
|---|---|---|
| Maker | StepFun | Thinking Machines |
| Weights | Open weights | Open weights |
| Released | October 8, 2026 | July 30, 2026 |
| Context window | 1.05M | 524K |
| Input $/Mtok | $1.00 | $0.45 |
| Output $/Mtok | $2.70 | $1.20 |
| Coding index | 61.1 | 27.3 |
| Independent measurements behind it | 4 | 4 |
| Cost per solved task | Not computable | $0.16 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Step 5 Preview better than Inkling Small for coding?
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 27.3 for Inkling Small. Pick Inkling Small for output tokens 2.3x cheaper ($1.20 vs $2.70 per million) and work measured by LMArena Text: math or Public Benefits Bench (Vals AI), where it leads.
Which is cheaper, Step 5 Preview or Inkling Small?
Step 5 Preview costs $1.00 per million input tokens and $2.70 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 5 Preview or Inkling Small?
Step 5 Preview, with 1.05M tokens against 524K.
How many benchmarks is the Step 5 Preview vs Inkling Small comparison based on?
48 benchmarks have a result for both models as of October 22, 2026. Step 5 Preview's coding index rests on 4 independent benchmarks and Inkling Small's on 4. Where only one model has a result, the page says so instead of naming a winner.