Grok 4.20 vs Kimi K2 Thinking
Grok 4.20 leads Kimi K2 Thinking on the Artificial Analysis Intelligence Index, 25.7 to 22.0, at about the same output price ($2.50 vs $2.50 per million). Updated October 21, 2026; 22 benchmarks have a result for both.
Grok 4.20 or Kimi K2 Thinking: which to pick
Only Grok 4.20 has a coding score, 33.3 on the Vibe Coding Index; Kimi K2 Thinking has none, so the two cannot be ranked on coding.
Pick Kimi K2 Thinking for a lower cost per solved task ($0.61 against $0.72) and work measured by LegalBench (Vals AI) or CaseLaw (Vals AI), where it leads.
- Shared results
- 22
- Grok 4.20 only
- 33
- Kimi K2 Thinking only
- 8
- Like-for-like categories
- 8 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
No call
Only Grok 4.20 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Grok 4.20
Grok 4.20 leads, 25.7 against 22.0.
Same board, both measured
Reasoning
GPQA Diamond
Grok 4.20
Grok 4.20 leads, 88.6% against 78.5%.
Same board, both measured
Math
AIME
Grok 4.20
Grok 4.20 leads, 96.5% against 85.4%.
Same board, both measured
Knowledge
MMLU Pro
Grok 4.20
Grok 4.20 leads, 86.3% against 81.1%.
Same board, both measured
Web design
Design Arena: websites
Grok 4.20
Grok 4.20 leads, 1229 against 1113.
Same board, both measured
Long documents
Listed context window
Grok 4.20
Grok 4.20 takes 2M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Kimi K2 Thinking
Grok 4.20 $0.0025, Kimi K2 Thinking $0.0019 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Kimi K2 Thinking
Grok 4.20 $0.72, Kimi K2 Thinking $0.61.
Published attempt cost and pass rate
At a glance
- Coding index
- Grok 4.20 33.3 from 2 benchmarks, Kimi K2 Thinking not benchmarked.
- Widest category
- Web design, 14.5 points apart on average over 1 shared benchmark.
- Widest single gap
- Terminal-Bench: Grok 4.20 57.3% against Kimi K2 Thinking 35.7%, 21.6 points apart on a 0 to 100 scale.
- Output price
- Both cost $2.50 per million output tokens.
- Context window
- Grok 4.20 takes 2M tokens, Kimi K2 Thinking 262K.
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 | Kimi K2 Thinking | Ties |
|---|---|---|---|---|
| Coding | 5 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 0 | 0 | 1 tie | |
| Reasoning | 3 | 0 | ||
| Math | 1 | 0 | ||
| Knowledge | 4 | 2 | ||
| Web design | 1 | 0 | ||
| General | 2 | 1 | ||
| All shared boards | 18 | 3 | 1 tie |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index50
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 63.4% | Only Kimi K2 Thinking measured |
| LiveCodeBench (Vals AI) | 84.3% | 63.1% | Grok 4.20 |
| SWE-bench Verified (Vals AI) | 72.2% | 60.2% | Grok 4.20 |
| Vibe Code Bench (Vals AI) | 4.1% | Not measured | Only Grok 4.20 measured |
| Code migration (Vals AI) | 0.3% | Not measured | Only Grok 4.20 measured |
| Terminal-Bench 2.1 (Vals AI) | 44.2% | Not measured | Only Grok 4.20 measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 85.3% | Only Kimi K2 Thinking measured |
| Terminal-Bench Hard (Artificial Analysis run) | 37.9% | 31.1% | Grok 4.20 |
| Terminal-Bench | 57.3% | 35.7% | Grok 4.20 |
| WeirdML | 52.3% | 42.8% | Grok 4.20 |
| ALE-Bench | Not measured | 597.5 | Only Kimi K2 Thinking measured |
| Neither model has a result on the other 28 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| AA Intelligence Index | 25.7 | 22.0 | Grok 4.20 |
| Epoch Capabilities Index | 152.1 | 145.8 | Grok 4.20 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index00
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| 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% | Not measured | Only Grok 4.20 measured |
| Tax Agent Bench (Vals AI) | 7.0% | Not measured | Only Grok 4.20 measured |
| Legal Research Bench (Vals AI) | 13.9% | Not measured | Only Grok 4.20 measured |
| Excel Modeling Benchmark (Vals AI) | 11.7% | Not measured | Only Grok 4.20 measured |
| τ²-Bench Telecom | 93.0% | 93.0% | Tie |
| METR time horizons | Not measured | 59.2% | Only Kimi K2 Thinking measured |
| Vending-Bench 2 | $4,663 | Not measured | Only Grok 4.20 measured |
| Neither model has a result on the other 28 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| GPQA Diamond | 88.6% | 78.5% | Grok 4.20 |
| MMMU Pro (Vals AI) | 83.5% | Not measured | Only Grok 4.20 measured |
| GPQA Diamond (Artificial Analysis run) | 91.1% | 83.8% | Grok 4.20 |
| Humanity's Last Exam (Artificial Analysis run) | 34.5% | 23.8% | Grok 4.20 |
| ARC-AGI | 89.5% | Not measured | Only Grok 4.20 measured |
| ARC-AGI-2 | 65.1% | Not measured | Only Grok 4.20 measured |
| Kagi LLM Benchmark | 75.0% | Not measured | Only Grok 4.20 measured |
| Neither model has a result on the other 15 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| AIME | 96.5% | 85.4% | Grok 4.20 |
| MGSM (Vals AI) | Not measured | 90.2% | Only Kimi K2 Thinking measured |
| AA Math Index | Not measured | 94.7 | Only Kimi K2 Thinking measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 94.7% | Only Kimi K2 Thinking measured |
| Neither model has a result on the other 9 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index42
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| MMLU Pro | 86.3% | 81.1% | Grok 4.20 |
| LegalBench (Vals AI) | 77.7% | 80.2% | Kimi K2 Thinking |
| CaseLaw (Vals AI) | 54.4% | 65.7% | Kimi K2 Thinking |
| CorpFin (Vals AI) | 63.7% | 60.6% | Grok 4.20 |
| TaxEval (Vals AI) | 74.1% | 71.7% | Grok 4.20 |
| MortgageTax (Vals AI) | 45.4% | Not measured | Only Grok 4.20 measured |
| MedQA (Vals AI) | 94.5% | 92.6% | Grok 4.20 |
| MedCode (Vals AI) | 32.2% | Not measured | Only Grok 4.20 measured |
| MMLU Pro (Artificial Analysis run) | Not measured | 84.8% | Only Kimi K2 Thinking measured |
| Neither model has a result on the other 9 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| Design Arena: websites | 1229 | 1113 | Grok 4.20 |
| 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 index21
| Benchmark | Grok 4.20 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 38.2% | Not measured | Only Grok 4.20 measured |
| MedScribe (Vals AI) | 63.4% | Not measured | Only Grok 4.20 measured |
| Vals Multimodal Index | 39.1% | Not measured | Only Grok 4.20 measured |
| IFBench | 81.2% | 68.1% | Grok 4.20 |
| Long context reasoning (AA-LCR) | 69.0% | 72.0% | Kimi K2 Thinking |
| DTBench | 90.1% | Not measured | Only Grok 4.20 measured |
| LMCA | 38.7% | Not measured | Only Grok 4.20 measured |
| CL-bench | 22.2% | 17.6% | Grok 4.20 |
| CL-bench Life | 11.9% | Not measured | Only Grok 4.20 measured |
| Neither model has a result on the other 37 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Grok 4.20 | Kimi K2 Thinking | 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
Kimi K2 Thinking costs less
Repository review
50K input + 3K output tokens
Kimi K2 Thinking costs less
Agent loop
200K input + 10K output tokens
Kimi K2 Thinking 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 | MoonshotAI Kimi K2 Thinking |
|---|---|---|
| Maker | xAI | Moonshot AI |
| Weights | No public weights listed | Open weights |
| Released | March 31, 2026 | November 6, 2025 |
| Context window | 2M | 262K |
| Input $/Mtok | $1.25 | $0.60 |
| Output $/Mtok | $2.50 | $2.50 |
| Coding index | 33.3 | Not benchmarked |
| Independent measurements behind it | 2 | 1 |
| Cost per solved task | $0.72 | $0.61 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Grok 4.20 better than Kimi K2 Thinking for coding?
Only Grok 4.20 has a coding score, 33.3 on the Vibe Coding Index; Kimi K2 Thinking has none, so the two cannot be ranked on coding. Pick Kimi K2 Thinking for a lower cost per solved task ($0.61 against $0.72) and work measured by LegalBench (Vals AI) or CaseLaw (Vals AI), where it leads.
Which is cheaper, Grok 4.20 or Kimi K2 Thinking?
Grok 4.20 costs $1.25 per million input tokens and $2.50 per million output tokens; Kimi K2 Thinking costs $0.60 and $2.50. Per solved SWE-bench Verified task, Grok 4.20 costs $0.72 and Kimi K2 Thinking $0.61.
Which has the bigger context window, Grok 4.20 or Kimi K2 Thinking?
Grok 4.20, with 2M tokens against 262K.
How many benchmarks is the Grok 4.20 vs Kimi K2 Thinking comparison based on?
22 benchmarks have a result for both models as of October 21, 2026. Grok 4.20's coding index rests on 2 independent benchmarks and Kimi K2 Thinking's on 1. Where only one model has a result, the page says so instead of naming a winner.