Grok 4.20 vs Inkling Small
Grok 4.20 leads Inkling Small on coding, 33.3 to 27.3 on the Vibe Coding Index, and Inkling Small costs 2.1x less per output token ($1.20 vs $2.50 per million). Updated October 21, 2026; 26 benchmarks have a result for both.
Grok 4.20 or Inkling Small: which to pick
Pick Grok 4.20 for coding: it scores 33.3 on the Vibe Coding Index against 27.3 for Inkling Small, though on 2 benchmarks against 4.
Pick Inkling Small for output tokens 2.1x cheaper ($1.20 vs $2.50 per million) and a lower cost per solved task ($0.16 against $0.72).
- Shared results
- 26
- Grok 4.20 only
- 28
- Inkling Small only
- 58
- 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
Grok 4.20
Grok 4.20 scores 33.3 against 27.3.
2 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
No call
Tied at 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
Grok 4.20
Grok 4.20 leads, 88.6% against 83.6%.
Same board, both measured
Math
AIME
No call
Only Grok 4.20 has a AIME result, 96.5%.
Directional only
Knowledge
MMLU Pro
Grok 4.20
Grok 4.20 leads, 86.3% against 85.6%.
Same board, both measured
Web design
Design Arena: websites
No call
Only Grok 4.20 has a Design Arena: websites result, 1229.
Directional only
General
Vals Index
No call
Only Inkling Small has a Vals Index result, 27.6%.
Directional only
Long documents
Listed context window
Grok 4.20
Grok 4.20 takes 2M tokens against 524K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling Small
Grok 4.20 $0.0025, Inkling Small $0.0010 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Inkling Small
Grok 4.20 $0.72, Inkling Small $0.16.
Published attempt cost and pass rate
At a glance
- Coding index
- Grok 4.20 33.3 from 2 benchmarks, Inkling Small 27.3 from 4 benchmarks.
- Widest category
- Agentic work, 13.2 points apart on average over 4 shared benchmarks.
- Widest single gap
- ARC-AGI-2: Grok 4.20 65.1% against Inkling Small 40.1%, 25.0 points apart on a 0 to 100 scale.
- Output price
- Grok 4.20 $2.50 against Inkling Small $1.20 per million output tokens, 2.1x apart.
- Context window
- Grok 4.20 takes 2M 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 | Grok 4.20 | Bars | Inkling Small | Ties |
|---|---|---|---|---|
| Coding | 0 | 5 | ||
| Intelligence | 1 | 0 | 1 tie | |
| Agentic work | 0 | 4 | ||
| Reasoning | 5 | 0 | ||
| Knowledge | 1 | 5 | ||
| General | 1 | 3 | ||
| All shared boards | 8 | 17 | 1 tie |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index05
| Benchmark | Grok 4.20 | 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) | 84.3% | 85.9% | Inkling Small |
| SWE-bench Verified (Vals AI) | 72.2% | 82.2% | Inkling Small |
| Terminal-Bench 4 (Vals AI) | Not measured | 0.0% | Only Inkling Small measured |
| Vibe Code Bench (Vals AI) | 4.1% | 19.1% | Inkling Small |
| Code migration (Vals AI) | 0.3% | 13.7% | Inkling Small |
| 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) | 44.2% | 55.1% | Inkling Small |
| 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) | 37.9% | Not measured | Only Grok 4.20 measured |
| Terminal-Bench | 57.3% | Not measured | Only Grok 4.20 measured |
| WeirdML | 52.3% | Not measured | Only Grok 4.20 measured |
| LMArena Text: coding | Not measured | 1450 | Only Inkling Small measured |
| LMArena Text: software and IT | Not measured | 1447 | Only Inkling Small measured |
| 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 17 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Grok 4.20 | Inkling Small | Leader |
|---|---|---|---|
| AA Intelligence Index | 25.7 | 25.7 | Tie |
| Epoch Capabilities Index | 152.1 | 150.3 | Grok 4.20 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | Grok 4.20 | Inkling Small | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 23.5 | Only Inkling Small measured |
| Design Arena: agents building web apps | 1144 | Not measured | Only Grok 4.20 measured |
| Design Arena: agents building full-stack apps | 1054 | Not measured | Only Grok 4.20 measured |
| Design Arena: agents building mobile apps | 1090 | Not measured | Only Grok 4.20 measured |
| Design Arena: agents building Android apps | 1052 | Not measured | Only Grok 4.20 measured |
| Design Arena: agents building Godot games | 1089 | Not measured | Only Grok 4.20 measured |
| Design Arena: HTML slides | 1180 | Not measured | Only Grok 4.20 measured |
| Finance Agent (Vals AI) | 28.5% | 41.3% | Inkling Small |
| Tax Agent Bench (Vals AI) | 7.0% | 15.4% | Inkling Small |
| Legal Research Bench (Vals AI) | 13.9% | 25.5% | Inkling Small |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 2.9% | Only Inkling Small measured |
| Excel Modeling Benchmark (Vals AI) | 11.7% | 31.8% | Inkling Small |
| τ²-Bench Telecom | 93.0% | Not measured | Only Grok 4.20 measured |
| Vending-Bench 2 | $4,663 | Not measured | Only Grok 4.20 measured |
| Neither model has a result on the other 25 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Grok 4.20 | Inkling Small | Leader |
|---|---|---|---|
| GPQA Diamond | 88.6% | 83.6% | Grok 4.20 |
| MMMU Pro (Vals AI) | 83.5% | Not measured | Only Grok 4.20 measured |
| GPQA Diamond (Artificial Analysis run) | 91.1% | 89.5% | Grok 4.20 |
| Humanity's Last Exam (Artificial Analysis run) | 34.5% | 33.3% | Grok 4.20 |
| GPQA Diamond (Epoch AI run) | Not measured | 88.5% | Only Inkling Small measured |
| ARC-AGI | 89.5% | 84.0% | Grok 4.20 |
| ARC-AGI-2 | 65.1% | 40.1% | Grok 4.20 |
| Mystery game puzzles | Not measured | 6.0% | Only Inkling Small measured |
| LMArena Text: hard prompts | Not measured | 1423 | Only Inkling Small measured |
| LMArena Text: expert | Not measured | 1441 | Only Inkling Small measured |
| LMArena Text: hard prompts in English | Not measured | 1429 | Only Inkling Small measured |
| 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 8 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
| Benchmark | Grok 4.20 | Inkling Small | Leader |
|---|---|---|---|
| AIME | 96.5% | Not measured | Only Grok 4.20 measured |
| 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 | Not measured | 1459 | Only Inkling Small measured |
| LMArena Text: mathematical work | Not measured | 1441 | Only Inkling Small measured |
| Neither model has a result on the other 6 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index15
| Benchmark | Grok 4.20 | Inkling Small | Leader |
|---|---|---|---|
| MMLU Pro | 86.3% | 85.6% | Grok 4.20 |
| LegalBench (Vals AI) | 77.7% | 83.0% | Inkling Small |
| CaseLaw (Vals AI) | 54.4% | Not measured | Only Grok 4.20 measured |
| CorpFin (Vals AI) | 63.7% | 69.6% | Inkling Small |
| TaxEval (Vals AI) | 74.1% | 75.5% | Inkling Small |
| MortgageTax (Vals AI) | 45.4% | 62.3% | Inkling Small |
| MedQA (Vals AI) | 94.5% | Not measured | Only Grok 4.20 measured |
| MedCode (Vals AI) | 32.2% | 37.9% | Inkling Small |
| SimpleQA Verified | Not measured | 19.1% | Only Inkling Small measured |
| LMArena Text: science | Not measured | 1428 | Only Inkling Small measured |
| LMArena Text: medicine and healthcare | Not measured | 1413 | Only Inkling Small measured |
| LMArena Text: legal and government | Not measured | 1415 | Only Inkling Small measured |
| LMArena Text: business and finance | Not measured | 1413 | Only Inkling Small 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 | Grok 4.20 | Inkling Small | Leader |
|---|---|---|---|
| Design Arena: websites | 1229 | Not measured | Only Grok 4.20 measured |
| Design Arena: UI components | 1199 | Not measured | Only Grok 4.20 measured |
| Design Arena: game dev | 1192 | Not measured | Only Grok 4.20 measured |
| Design Arena: data viz | 1217 | Not measured | Only Grok 4.20 measured |
| Design Arena: 3D | 1193 | Not measured | Only Grok 4.20 measured |
| Design Arena: all code categories | 1221 | Not measured | Only Grok 4.20 measured |
| Design Arena: SVG | 1164 | Not measured | Only Grok 4.20 measured |
| Design Arena: ASCII art | 1174 | Not measured | Only Grok 4.20 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index13
| Benchmark | Grok 4.20 | 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) | 38.2% | 32.7% | Grok 4.20 |
| MedScribe (Vals AI) | 63.4% | 84.1% | Inkling Small |
| Vals Multimodal Index | 39.1% | 50.0% | Inkling Small |
| IFBench | 81.2% | Not measured | Only Grok 4.20 measured |
| Long context reasoning (AA-LCR) | 69.0% | 75.7% | Inkling Small |
| DTBench | 90.1% | Not measured | Only Grok 4.20 measured |
| LMCA | 38.7% | Not measured | Only Grok 4.20 measured |
| CL-bench | 22.2% | Not measured | Only Grok 4.20 measured |
| CL-bench Life | 11.9% | Not measured | Only Grok 4.20 measured |
| LMArena Text | Not measured | 1413 | Only Inkling Small measured |
| LMArena Text: instruction following | Not measured | 1399 | Only Inkling Small measured |
| LMArena Text: creative writing | Not measured | 1334 | Only Inkling Small measured |
| LMArena Vision | Not measured | 1237 | Only Inkling Small measured |
| LMArena Text: English | Not measured | 1421 | Only Inkling Small measured |
| LMArena Text: non-English | Not measured | 1401 | Only Inkling Small measured |
| LMArena Text: Chinese | Not measured | 1464 | Only Inkling Small measured |
| LMArena Text: German | Not measured | 1408 | Only Inkling Small measured |
| LMArena Text: Japanese | Not measured | 1401 | Only Inkling Small measured |
| LMArena Text: Korean | Not measured | 1367 | Only Inkling Small measured |
| LMArena Text: French | Not measured | 1435 | Only Inkling Small measured |
| LMArena Text: Spanish | Not measured | 1422 | Only Inkling Small measured |
| LMArena Text: Russian | Not measured | 1394 | Only Inkling Small measured |
| LMArena Text: Polish | Not measured | 1428 | Only Inkling Small measured |
| LMArena Text: multi-turn | Not measured | 1416 | Only Inkling Small measured |
| LMArena Text: longer queries | Not measured | 1402 | Only Inkling Small measured |
| LMArena Text: writing and language | Not measured | 1357 | Only Inkling Small measured |
| LMArena Text: entertainment and media | Not measured | 1352 | Only Inkling Small measured |
| 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 12 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Grok 4.20 | 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 | SpaceXAI Grok 4.20 | Thinking Machines Inkling Small |
|---|---|---|
| Maker | xAI | Thinking Machines |
| Weights | No public weights listed | Open weights |
| Released | March 31, 2026 | July 30, 2026 |
| Context window | 2M | 524K |
| Input $/Mtok | $1.25 | $0.45 |
| Output $/Mtok | $2.50 | $1.20 |
| Coding index | 33.3 | 27.3 |
| Independent measurements behind it | 2 | 4 |
| Cost per solved task | $0.72 | $0.16 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Grok 4.20 better than Inkling Small for coding?
Pick Grok 4.20 for coding: it scores 33.3 on the Vibe Coding Index against 27.3 for Inkling Small, though on 2 benchmarks against 4. Pick Inkling Small for output tokens 2.1x cheaper ($1.20 vs $2.50 per million) and a lower cost per solved task ($0.16 against $0.72).
Which is cheaper, Grok 4.20 or Inkling Small?
Grok 4.20 costs $1.25 per million input tokens and $2.50 per million output tokens; Inkling Small costs $0.45 and $1.20. Per solved SWE-bench Verified task, Grok 4.20 costs $0.72 and Inkling Small $0.16.
Which has the bigger context window, Grok 4.20 or Inkling Small?
Grok 4.20, with 2M tokens against 524K.
How many benchmarks is the Grok 4.20 vs Inkling Small comparison based on?
26 benchmarks have a result for both models as of October 21, 2026. Grok 4.20's coding index rests on 2 independent benchmarks and Inkling Small's on 4. Where only one model has a result, the page says so instead of naming a winner.