Model comparison
Kimi K2 (Jul 2025) vs Yi-Lightning
Kimi K2 (Jul 2025) is the stronger model overall, scoring 41.2 to 37.1 on the Noometry Index.
Last verified . 18 shared benchmarks.
Summary
- They share 18 benchmarks with published results for both. Kimi K2 (Jul 2025) scores higher in 7 categories and Yi-Lightning in 1 category; 8 gaps are clear of the uncertainty.
- The widest gap is in coding, where Kimi K2 (Jul 2025) leads 42.4 to 27.4.
- The biggest single-benchmark swing is Aider Polyglot: 59.1% for Kimi K2 (Jul 2025) and 12.9% for Yi-Lightning.
- Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.
Side by side
| Kimi K2 (Jul 2025) | Yi-Lightning | |
|---|---|---|
| Provider | Moonshot AI | 01.AI |
| Noometry Index | 41.2 | 37.1 |
| Released | 2025-07-12 | 2024-12-02 |
| Weights | Open | Proprietary |
| Context window | 262K | — |
| Max output | 262K | — |
| Input $ / M tokens | $0.57 | — |
| Output $ / M tokens | $2.30 | — |
| Results tracked | 42 | 18 |
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Category by category
Coding Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 42.4 (#102), Yi-Lightning: 27.4 (#320)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| Aider Polyglot | 59.1% | 12.9% |
| LMArena Coding | 1399 | 1312 |
| SWE-bench Verified (bash only) | 63.4% | — |
| GSO | 4.9% | — |
| WeirdML | 42.8% | — |
| ALE-Bench | 597.5 | — |
Agentic & Tool Use Not comparable
Kimi K2 (Jul 2025): 32.4 (#64), Yi-Lightning: —
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| Terminal-Bench | 35.7% | — |
| Berkeley Function Calling Leaderboard | 59.1% | — |
| METR Time Horizons | 59.2% | — |
Reasoning Yi-Lightning leads
Kimi K2 (Jul 2025): 23.3 (#179), Yi-Lightning: 25.9 (#139)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| LMArena Hard Prompts | 1384 | 1302 |
| SimpleBench | 26.3% | — |
| Kagi LLM Benchmark | 64.4% | — |
| Epoch Capabilities Index | 146.01 | — |
| ForecastBench | 60.2 | — |
Math Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 42.7 (#83), Yi-Lightning: 36.2 (#172)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| LMArena Math | 1397 | 1300 |
| Omni-MATH | 65.4% | — |
| FrontierMath (Feb 2025 set) | 21.4% | — |
| FrontierMath Tier 4 (v1) | 0% | — |
Knowledge Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 37.3 (#157), Yi-Lightning: 35.4 (#185)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| LMArena Expert | 1365 | 1286 |
| MMLU-Pro | 81.9% | — |
| Confabulations | 20.4% | — |
| Vectara Hallucination Rate | 17.9% | — |
| GPQA (HELM) | 65.3% | — |
Multilingual Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 49.6 (#130), Yi-Lightning: 42.2 (#196)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| LMArena Non-English | 1372 | 1269 |
| LMArena Chinese | 1415 | 1320 |
| LMArena French | 1379 | 1305 |
| LMArena German | 1387 | 1267 |
| LMArena Japanese | 1349 | 1228 |
| LMArena Korean | 1325 | 1192 |
| LMArena Russian | 1385 | 1255 |
| LMArena Spanish | 1386 | 1315 |
Instruction Following Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 71.1 (#156), Yi-Lightning: 67.4 (#196)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| LMArena Instruction Following | 1348 | 1278 |
| IFEval | 85% | — |
Long Context Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 41.2 (#145), Yi-Lightning: 39.4 (#181)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| LMArena Longer Query | 1353 | 1297 |
| Fiction.LiveBench | 66.7% | — |
| CL-bench | 17.6% | — |
Writing & Preference Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 62.3 (#78), Yi-Lightning: 50.2 (#184)
| Benchmark | Kimi K2 (Jul 2025) | Yi-Lightning |
|---|---|---|
| LMArena Text | 1380 | 1302 |
| LMArena Creative Writing | 1350 | 1280 |
| LMArena Multi-Turn | 1371 | 1311 |
| Short-Story Creative Writing | 85.6% | — |
| EQ-Bench Creative Writing | 1666 | — |
| WildBench | 86.2% | — |
Frequently asked questions
Is Kimi K2 (Jul 2025) better than Yi-Lightning?
Kimi K2 (Jul 2025) is the stronger model overall, scoring 41.2 to 37.1 on the Noometry Index.
Is Kimi K2 (Jul 2025) or Yi-Lightning better for coding?
Kimi K2 (Jul 2025) scores higher on coding benchmarks: 42.4 versus 27.4 in the Noometry coding category.
How many benchmarks do Kimi K2 (Jul 2025) and Yi-Lightning share?
18 benchmarks have published results for both models. Kimi K2 (Jul 2025) has 42 scored results on Noometry and Yi-Lightning has 18.