Claude Opus 4.1 vs Kimi K2 Thinking
Claude Opus 4.1 leads Kimi K2 Thinking on the Artificial Analysis Intelligence Index, 22.8 to 22.0, and Kimi K2 Thinking costs 30.0x less per output token ($2.50 vs $75.00 per million). Updated October 22, 2026; 14 benchmarks have a result for both.
Claude Opus 4.1 or Kimi K2 Thinking: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Claude Opus 4.1 for work measured by Epoch Capabilities Index or GPQA Diamond, where it leads.
- Shared results
- 14
- Claude Opus 4.1 only
- 59
- Kimi K2 Thinking only
- 16
- 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
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
Claude Opus 4.1
Claude Opus 4.1 leads, 22.8 against 22.0.
Same board, both measured
Reasoning
GPQA Diamond
Kimi K2 Thinking
Kimi K2 Thinking leads, 78.5% against 76.3%.
Same board, both measured
Math
AIME
Kimi K2 Thinking
Kimi K2 Thinking leads, 85.4% against 78.2%.
Same board, both measured
Knowledge
MMLU Pro
Claude Opus 4.1
Claude Opus 4.1 leads, 87.9% against 81.1%.
Same board, both measured
Web design
Design Arena: websites
Claude Opus 4.1
Claude Opus 4.1 leads, 1176 against 1113.
Same board, both measured
Long documents
Listed context window
Kimi K2 Thinking
Kimi K2 Thinking takes 262K tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Kimi K2 Thinking
Claude Opus 4.1 $0.052, Kimi K2 Thinking $0.0019 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Kimi K2 Thinking has the number, $0.61.
Directional only
At a glance
- Coding index
- Claude Opus 4.1 not benchmarked, Kimi K2 Thinking not benchmarked.
- Widest category
- Web design, 7.9 points apart on average over 1 shared benchmark.
- Widest single gap
- Design Arena: websites: Claude Opus 4.1 1176 against Kimi K2 Thinking 1113, 7.9 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.1 $75.00 against Kimi K2 Thinking $2.50 per million output tokens, 30.0x apart.
- Context window
- Claude Opus 4.1 takes 200K 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 | Claude Opus 4.1 | Bars | Kimi K2 Thinking | Ties |
|---|---|---|---|---|
| Coding | 3 | 0 | ||
| Intelligence | 1 | 1 | ||
| Agentic work | 1 | 0 | ||
| Reasoning | 0 | 1 | ||
| Math | 1 | 1 | ||
| Knowledge | 4 | 0 | ||
| Web design | 1 | 0 | ||
| All shared boards | 11 | 3 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index30
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 63.4% | Only Kimi K2 Thinking measured |
| LMArena WebDev | 1390 | Not measured | Only Claude Opus 4.1 measured |
| LiveCodeBench (Vals AI) | 66.5% | 63.1% | Claude Opus 4.1 |
| SWE-bench Verified (Vals AI) | Not measured | 60.2% | Only Kimi K2 Thinking measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 85.3% | Only Kimi K2 Thinking measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 31.1% | Only Kimi K2 Thinking measured |
| Terminal-Bench | 38.0% | 35.7% | Claude Opus 4.1 |
| WeirdML | 45.9% | 42.8% | Claude Opus 4.1 |
| Cybench | 42.0% | Not measured | Only Claude Opus 4.1 measured |
| ALE-Bench | Not measured | 597.5 | Only Kimi K2 Thinking measured |
| LMArena Text: coding | 1479 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: software and IT | 1456 | Not measured | Only Claude Opus 4.1 measured |
| LMArena WebDev: HTML | 1399 | Not measured | Only Claude Opus 4.1 measured |
| SciCode | 4.6% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 25 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.8 | 22.0 | Claude Opus 4.1 |
| Epoch Capabilities Index | 144.1 | 145.8 | Kimi K2 Thinking |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| τ²-Bench Telecom | Not measured | 93.0% | Only Kimi K2 Thinking measured |
| METR time horizons | 66.8% | 59.2% | Claude Opus 4.1 |
| GDPval | 43.6% | Not measured | Only Claude Opus 4.1 measured |
| DeepResearch Bench | 48.3% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 37 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| GPQA Diamond | 76.3% | 78.5% | Kimi K2 Thinking |
| MMMU Pro (Vals AI) | 77.5% | Not measured | Only Claude Opus 4.1 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 83.8% | Only Kimi K2 Thinking measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 23.8% | Only Kimi K2 Thinking measured |
| GPQA Diamond (Epoch AI run) | 77.3% | Not measured | Only Claude Opus 4.1 measured |
| SimpleBench | 60.0% | Not measured | Only Claude Opus 4.1 measured |
| Mystery game puzzles | 21.0% | Not measured | Only Claude Opus 4.1 measured |
| EBR-bench | 7.9% | Not measured | Only Claude Opus 4.1 measured |
| VPCT | 35.0% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: hard prompts | 1442 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: expert | 1438 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: hard prompts in English | 1451 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 10 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| AIME | 78.2% | 85.4% | Kimi K2 Thinking |
| MATH 500 (Vals AI) | 95.4% | Not measured | Only Claude Opus 4.1 measured |
| MGSM (Vals AI) | 94.4% | 90.2% | Claude Opus 4.1 |
| 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 |
| OTIS Mock AIME | 68.9% | Not measured | Only Claude Opus 4.1 measured |
| FrontierMath, tiers 1 to 3 | 12.6% | Not measured | Only Claude Opus 4.1 measured |
| FrontierMath, tier 4 | 2.4% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: math | 1431 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: mathematical work | 1434 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| MMLU Pro | 87.9% | 81.1% | Claude Opus 4.1 |
| LegalBench (Vals AI) | 83.5% | 80.2% | Claude Opus 4.1 |
| CaseLaw (Vals AI) | Not measured | 65.7% | Only Kimi K2 Thinking measured |
| CorpFin (Vals AI) | Not measured | 60.6% | Only Kimi K2 Thinking measured |
| TaxEval (Vals AI) | 73.7% | 71.7% | Claude Opus 4.1 |
| MortgageTax (Vals AI) | 61.1% | Not measured | Only Claude Opus 4.1 measured |
| MedQA (Vals AI) | 93.6% | 92.6% | Claude Opus 4.1 |
| MedCode (Vals AI) | 47.2% | Not measured | Only Claude Opus 4.1 measured |
| MMLU Pro (Artificial Analysis run) | Not measured | 84.8% | Only Kimi K2 Thinking measured |
| LMArena Text: science | 1422 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: medicine and healthcare | 1416 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: legal and government | 1421 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: business and finance | 1406 | Not measured | Only Claude Opus 4.1 measured |
| FACTS Benchmark Suite | 40.4% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 4 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| Design Arena: websites | 1176 | 1113 | Claude Opus 4.1 |
| Design Arena: UI components | 1162 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: game dev | 1171 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: data viz | 1166 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: 3D | 1152 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: all code categories | 1170 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: SVG | 1152 | Not measured | Only Claude Opus 4.1 measured |
| Design Arena: ASCII art | 1167 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 1 board here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index25 boards, none shared
| Benchmark | Claude Opus 4.1 | Kimi K2 Thinking | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 31.4% | Not measured | Only Claude Opus 4.1 measured |
| MedScribe (Vals AI) | 73.9% | Not measured | Only Claude Opus 4.1 measured |
| IFBench | Not measured | 68.1% | Only Kimi K2 Thinking measured |
| Long context reasoning (AA-LCR) | Not measured | 72.0% | Only Kimi K2 Thinking measured |
| DTBench | 80.0% | Not measured | Only Claude Opus 4.1 measured |
| LMCA | 37.1% | Not measured | Only Claude Opus 4.1 measured |
| Creative writing (Lech Mazur) | 84.7% | Not measured | Only Claude Opus 4.1 measured |
| CL-bench | Not measured | 17.6% | Only Kimi K2 Thinking measured |
| LMArena Text | 1419 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: instruction following | 1435 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: creative writing | 1412 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: English | 1433 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: non-English | 1405 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Chinese | 1427 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: German | 1413 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Japanese | 1377 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Korean | 1381 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: French | 1433 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Spanish | 1448 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Russian | 1422 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Polish | 1413 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: multi-turn | 1444 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: longer queries | 1455 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: writing and language | 1418 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: entertainment and media | 1398 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 21 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.1 | 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 | Anthropic Claude Opus 4.1 | MoonshotAI Kimi K2 Thinking |
|---|---|---|
| Maker | Anthropic | Moonshot AI |
| Weights | No public weights listed | Open weights |
| Released | August 5, 2025 | November 6, 2025 |
| Context window | 200K | 262K |
| Input $/Mtok | $15.00 | $0.60 |
| Output $/Mtok | $75.00 | $2.50 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 1 | 1 |
| Cost per solved task | Not computable | $0.61 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.1 better than Kimi K2 Thinking for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Claude Opus 4.1 for work measured by Epoch Capabilities Index or GPQA Diamond, where it leads.
Which is cheaper, Claude Opus 4.1 or Kimi K2 Thinking?
Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; Kimi K2 Thinking costs $0.60 and $2.50. Cost per solved task is known for Kimi K2 Thinking only.
Which has the bigger context window, Claude Opus 4.1 or Kimi K2 Thinking?
Kimi K2 Thinking, with 262K tokens against 200K.
How many benchmarks is the Claude Opus 4.1 vs Kimi K2 Thinking comparison based on?
14 benchmarks have a result for both models as of October 22, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and Kimi K2 Thinking's on 1. Where only one model has a result, the page says so instead of naming a winner.