Kimi K2 Thinking vs o3
Updated October 21, 2026. 27 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick o3 for coding: it scores 70.7 on the Vibe Coding Index against 63.4 for Kimi K2 Thinking.
Pick Kimi K2 Thinking when output tokens cost 3.2x less, or when the context window is larger, 262K against 200K tokens.
- Shared results
- 27
- Kimi K2 Thinking only
- 3
- o3 only
- 70
- Like-for-like categories
- 8 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, four public coding benchmarks
o3
o3 scores 70.7 against 63.4.
1 and 2 benchmarks behind the scores
Intelligence
AA Intelligence Index
Kimi K2 Thinking
Kimi K2 Thinking leads, 22.0 against 20.2.
Same board, both measured
Reasoning
GPQA Diamond
o3
o3 leads, 84.1% against 78.5%.
Same board, both measured
Math
AIME
Kimi K2 Thinking
Kimi K2 Thinking leads, 85.4% against 85.3%.
Same board, both measured
Knowledge
MMLU Pro
o3
o3 leads, 85.6% against 81.1%.
Same board, both measured
Web design
Design Arena: websites
Kimi K2 Thinking
Kimi K2 Thinking leads, 1113 against 1036.
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
Kimi K2 Thinking $0.0019, o3 $0.0060 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
o3
Kimi K2 Thinking $0.61, o3 $0.571.
Published attempt cost and pass rate
At a glance
- Coding index
- Kimi K2 Thinking 63.4 from 1 benchmark, o3 70.7 from 2 benchmarks.
- Widest category
- Web design, 9.6 points apart on average over 1 shared benchmark.
- Widest single gap
- LiveCodeBench (Vals AI): Kimi K2 Thinking 63.1% against o3 83.9%, 20.8 points apart on a 0 to 100 scale.
- Output price
- Kimi K2 Thinking $2.50 against o3 $8.00 per million output tokens, 3.2x apart.
- Context window
- Kimi K2 Thinking takes 262K tokens, o3 200K.
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 | Kimi K2 Thinking | Bars | o3 | Ties |
|---|---|---|---|---|
| Coding | 2 | 4 | ||
| Intelligence | 1 | 1 | ||
| Agentic work | 1 | 1 | ||
| Reasoning | 2 | 1 | ||
| Math | 3 | 1 | ||
| Knowledge | 1 | 5 | ||
| Web design | 1 | 0 | ||
| General | 0 | 3 | ||
| All shared boards | 11 | 16 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index24
| Benchmark | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 81.3% | Only o3 measured |
| SWE-bench Verified | 63.4% | 58.4% | Kimi K2 Thinking |
| SWE-bench Multimodal | Not measured | 36.0% | Only o3 measured |
| LiveCodeBench (Vals AI) | 63.1% | 83.9% | o3 |
| SWE-bench Verified (Vals AI) | 60.2% | Not measured | Only Kimi K2 Thinking measured |
| LiveCodeBench (Artificial Analysis run) | 85.3% | 80.8% | Kimi K2 Thinking |
| Terminal-Bench Hard (Artificial Analysis run) | 31.1% | 37.1% | o3 |
| Terminal-Bench | 35.7% | Not measured | Only Kimi K2 Thinking measured |
| GSO-Bench | Not measured | 8.8% | Only o3 measured |
| WeirdML | 42.8% | 52.4% | o3 |
| ALE-Bench | 597.5 | 933.5 | o3 |
| LMArena Text: coding | Not measured | 1407 | Only o3 measured |
| LMArena Text: software and IT | Not measured | 1415 | Only o3 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 | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.0 | 20.2 | Kimi K2 Thinking |
| Epoch Capabilities Index | 145.8 | 146.7 | o3 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| τ²-Bench Telecom | 93.0% | 80.7% | Kimi K2 Thinking |
| METR time horizons | 59.2% | 65.4% | o3 |
| GDPval | Not measured | 30.8% | Only o3 measured |
| DeepResearch Bench | Not measured | 45.2% | Only o3 measured |
| OSWorld | Not measured | 23.0% | Only o3 measured |
| Neither model has a result on the other 34 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index21
| Benchmark | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| GPQA Diamond | 78.5% | 84.1% | o3 |
| MMMU Pro (Vals AI) | Not measured | 80.4% | Only o3 measured |
| GPQA Diamond (Artificial Analysis run) | 83.8% | 82.7% | Kimi K2 Thinking |
| Humanity's Last Exam (Artificial Analysis run) | 23.8% | 20.1% | Kimi K2 Thinking |
| GPQA Diamond (Epoch AI run) | Not measured | 81.8% | Only o3 measured |
| ARC-AGI | Not measured | 60.8% | Only o3 measured |
| ARC-AGI-2 | Not measured | 6.5% | Only o3 measured |
| SimpleBench | Not measured | 53.1% | Only o3 measured |
| Chess puzzles | Not measured | 37.0% | Only o3 measured |
| Mystery game puzzles | Not measured | 29.0% | Only o3 measured |
| VPCT | Not measured | 52.0% | Only o3 measured |
| LMArena Text: hard prompts | Not measured | 1402 | Only o3 measured |
| LMArena Text: expert | Not measured | 1402 | Only o3 measured |
| LMArena Text: hard prompts in English | Not measured | 1411 | Only o3 measured |
| LMArena Vision: diagrams | Not measured | 1220 | Only o3 measured |
| LMArena Vision: homework | Not measured | 1234 | Only o3 measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index31
| Benchmark | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| AIME | 85.4% | 85.3% | Kimi K2 Thinking |
| MATH 500 (Vals AI) | Not measured | 94.6% | Only o3 measured |
| MGSM (Vals AI) | 90.2% | 91.8% | o3 |
| AA Math Index | 94.7 | 88.3 | Kimi K2 Thinking |
| AIME 2025 (Artificial Analysis run) | 94.7% | 88.3% | Kimi K2 Thinking |
| OTIS Mock AIME | Not measured | 84.4% | Only o3 measured |
| FrontierMath, tiers 1 to 3 | Not measured | 33.3% | Only o3 measured |
| MATH level 5 | Not measured | 97.8% | Only o3 measured |
| LMArena Text: math | Not measured | 1426 | Only o3 measured |
| LMArena Text: mathematical work | Not measured | 1423 | Only o3 measured |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index15
| Benchmark | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| MMLU Pro | 81.1% | 85.6% | o3 |
| LegalBench (Vals AI) | 80.2% | 83.8% | o3 |
| CaseLaw (Vals AI) | 65.7% | Not measured | Only Kimi K2 Thinking measured |
| CorpFin (Vals AI) | 60.6% | 59.7% | Kimi K2 Thinking |
| TaxEval (Vals AI) | 71.7% | 74.6% | o3 |
| MortgageTax (Vals AI) | Not measured | 65.7% | Only o3 measured |
| MedQA (Vals AI) | 92.6% | 96.1% | o3 |
| MedCode (Vals AI) | Not measured | 47.3% | Only o3 measured |
| MMLU Pro (Artificial Analysis run) | 84.8% | 85.3% | o3 |
| SimpleQA Verified | Not measured | 49.4% | Only o3 measured |
| GeoBench | Not measured | 74.0% | Only o3 measured |
| LMArena Text: science | Not measured | 1429 | Only o3 measured |
| LMArena Text: medicine and healthcare | Not measured | 1448 | Only o3 measured |
| LMArena Text: legal and government | Not measured | 1428 | Only o3 measured |
| LMArena Text: business and finance | Not measured | 1393 | Only o3 measured |
| Neither model has a result on the other 2 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1113 | 1036 | Kimi K2 Thinking |
| Design Arena: UI components | Not measured | 1016 | Only o3 measured |
| Design Arena: game dev | Not measured | 1034 | Only o3 measured |
| Design Arena: data viz | Not measured | 1200 | Only o3 measured |
| Design Arena: all code categories | Not measured | 1021 | Only o3 measured |
| Neither model has a result on the other 4 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Kimi K2 Thinking | o3 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | Not measured | 41.8% | Only o3 measured |
| MedScribe (Vals AI) | Not measured | 76.7% | Only o3 measured |
| IFBench | 68.1% | 71.4% | o3 |
| Long context reasoning (AA-LCR) | 72.0% | 74.7% | o3 |
| DTBench | Not measured | 84.8% | Only o3 measured |
| LMCA | Not measured | 39.7% | Only o3 measured |
| Fiction.LiveBench | Not measured | 88.9% | Only o3 measured |
| Creative writing (Lech Mazur) | Not measured | 83.9% | Only o3 measured |
| CL-bench | 17.6% | 17.8% | o3 |
| LMArena Text | Not measured | 1410 | Only o3 measured |
| LMArena Text: instruction following | Not measured | 1368 | Only o3 measured |
| LMArena Text: creative writing | Not measured | 1359 | Only o3 measured |
| LMArena Vision | Not measured | 1214 | Only o3 measured |
| LMArena Text: English | Not measured | 1417 | Only o3 measured |
| LMArena Text: non-English | Not measured | 1401 | Only o3 measured |
| LMArena Text: Chinese | Not measured | 1437 | Only o3 measured |
| LMArena Text: German | Not measured | 1420 | Only o3 measured |
| LMArena Text: Japanese | Not measured | 1403 | Only o3 measured |
| LMArena Text: Korean | Not measured | 1370 | Only o3 measured |
| LMArena Text: French | Not measured | 1430 | Only o3 measured |
| LMArena Text: Spanish | Not measured | 1395 | Only o3 measured |
| LMArena Text: Russian | Not measured | 1406 | Only o3 measured |
| LMArena Text: Polish | Not measured | 1438 | Only o3 measured |
| LMArena Text: multi-turn | Not measured | 1405 | Only o3 measured |
| LMArena Text: longer queries | Not measured | 1372 | Only o3 measured |
| LMArena Text: writing and language | Not measured | 1372 | Only o3 measured |
| LMArena Text: entertainment and media | Not measured | 1373 | Only o3 measured |
| LMArena Vision: English | Not measured | 1221 | Only o3 measured |
| LMArena Vision: Chinese | Not measured | 1237 | Only o3 measured |
| LMArena Vision: reading text | Not measured | 1218 | Only o3 measured |
| LMArena Vision: humor | Not measured | 1222 | Only o3 measured |
| LMArena Vision: captioning | Not measured | 1210 | Only o3 measured |
| LMArena Vision: recognizing things | Not measured | 1234 | Only o3 measured |
| LMArena Vision: creative writing | Not measured | 1201 | Only o3 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 | Kimi K2 Thinking | o3 | 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 | MoonshotAI Kimi K2 Thinking | OpenAI o3 |
|---|---|---|
| Maker | Moonshot AI | OpenAI |
| Weights | Open weights | No public weights listed |
| Released | November 6, 2025 | April 16, 2025 |
| Context window | 262K | 200K |
| Input $/Mtok | $0.60 | $2.00 |
| Output $/Mtok | $2.50 | $8.00 |
| Coding index | 63.4 | 70.7 |
| Independent measurements behind it | 1 | 2 |
| Cost per solved task | $0.61 | $0.571 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Kimi K2 Thinking better than o3 for coding?
Pick o3 for coding: it scores 70.7 on the Vibe Coding Index against 63.4 for Kimi K2 Thinking. Pick Kimi K2 Thinking when output tokens cost 3.2x less, or when the context window is larger, 262K against 200K tokens.
Which is cheaper, Kimi K2 Thinking or o3?
Kimi K2 Thinking costs $0.60 per million input tokens and $2.50 per million output tokens; o3 costs $2.00 and $8.00. Per solved SWE-bench Verified task, Kimi K2 Thinking costs $0.61 and o3 $0.571.
Which has the bigger context window, Kimi K2 Thinking or o3?
Kimi K2 Thinking, with 262K tokens against 200K.
How many benchmarks is the Kimi K2 Thinking vs o3 comparison based on?
27 benchmarks have a result for both models as of October 21, 2026. Kimi K2 Thinking's coding index rests on 1 independent benchmark and o3's on 2. Where only one model has a result, the page says so instead of naming a winner.