Model comparison
Kimi K2 (Jul 2025) vs Step 2 16k Exp 202412
Kimi K2 (Jul 2025) is the stronger model overall, scoring 41.2 to 39.2 on the Noometry Index.
Last verified . 12 shared benchmarks.
StepFunSummary
- They share 12 benchmarks with published results for both. Kimi K2 (Jul 2025) scores higher in 7 categories and Step 2 16k Exp 202412 in 1 category; 8 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Kimi K2 (Jul 2025) leads 62.3 to 52.3.
- Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.
Side by side
| Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 | |
|---|---|---|
| Provider | Moonshot AI | StepFun |
| Noometry Index | 41.2 | 39.2 |
| Released | 2025-07-12 | — |
| Weights | Open | Proprietary |
| Context window | 262K | — |
| Max output | 262K | — |
| Input $ / M tokens | $0.57 | — |
| Output $ / M tokens | $2.30 | — |
| Results tracked | 42 | 12 |
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Category by category
Coding Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 42.4 (#102), Step 2 16k Exp 202412: 38.5 (#174)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Coding | 1399 | 1316 |
| SWE-bench Verified (bash only) | 63.4% | — |
| Aider Polyglot | 59.1% | — |
| GSO | 4.9% | — |
| WeirdML | 42.8% | — |
| ALE-Bench | 597.5 | — |
Agentic & Tool Use Not comparable
Kimi K2 (Jul 2025): 32.4 (#64), Step 2 16k Exp 202412: —
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| Terminal-Bench | 35.7% | — |
| Berkeley Function Calling Leaderboard | 59.1% | — |
| METR Time Horizons | 59.2% | — |
Reasoning Step 2 16k Exp 202412 leads
Kimi K2 (Jul 2025): 23.3 (#179), Step 2 16k Exp 202412: 25.9 (#142)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Hard Prompts | 1384 | 1299 |
| 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), Step 2 16k Exp 202412: 36.3 (#169)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Math | 1397 | 1304 |
| 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), Step 2 16k Exp 202412: 35.2 (#187)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Expert | 1365 | 1279 |
| 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), Step 2 16k Exp 202412: 43.7 (#181)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Non-English | 1372 | 1290 |
| LMArena Chinese | 1415 | 1331 |
| LMArena Russian | 1385 | 1324 |
| LMArena French | 1379 | — |
| LMArena German | 1387 | — |
| LMArena Japanese | 1349 | — |
| LMArena Korean | 1325 | — |
| LMArena Spanish | 1386 | — |
Instruction Following Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 71.1 (#156), Step 2 16k Exp 202412: 67.9 (#192)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Instruction Following | 1348 | 1287 |
| IFEval | 85% | — |
Long Context Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 41.2 (#145), Step 2 16k Exp 202412: 39.7 (#170)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Longer Query | 1353 | 1307 |
| Fiction.LiveBench | 66.7% | — |
| CL-bench | 17.6% | — |
Writing & Preference Kimi K2 (Jul 2025) leads
Kimi K2 (Jul 2025): 62.3 (#78), Step 2 16k Exp 202412: 52.3 (#173)
| Benchmark | Kimi K2 (Jul 2025) | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Text | 1380 | 1321 |
| LMArena Creative Writing | 1350 | 1328 |
| LMArena Multi-Turn | 1371 | 1292 |
| Short-Story Creative Writing | 85.6% | — |
| EQ-Bench Creative Writing | 1666 | — |
| WildBench | 86.2% | — |
Frequently asked questions
Is Kimi K2 (Jul 2025) better than Step 2 16k Exp 202412?
Kimi K2 (Jul 2025) is the stronger model overall, scoring 41.2 to 39.2 on the Noometry Index.
Is Kimi K2 (Jul 2025) or Step 2 16k Exp 202412 better for coding?
Kimi K2 (Jul 2025) scores higher on coding benchmarks: 42.4 versus 38.5 in the Noometry coding category.
How many benchmarks do Kimi K2 (Jul 2025) and Step 2 16k Exp 202412 share?
12 benchmarks have published results for both models. Kimi K2 (Jul 2025) has 42 scored results on Noometry and Step 2 16k Exp 202412 has 12.