# Kimi K2 (Jul 2025) vs Step 5 Preview

> Step 5 Preview is the stronger model overall, scoring 47.9 to 41.2 on the Noometry Index.

- Canonical page: https://noometry.com/compare/kimi-k2-vs-step-5-preview
- Last updated: 2026-10-12
- Shared benchmarks: 13

## Summary

- They share 13 benchmarks with published results for both. Kimi K2 (Jul 2025) scores higher in 0 categories and Step 5 Preview in 8 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Step 5 Preview leads 40.0 to 23.3.
- Kimi K2 (Jul 2025) is cheaper at $0.57 / $2.30 per million input/output tokens, against $1 / $2.70 for Step 5 Preview.
- Step 5 Preview accepts more context: 1.02M tokens versus 262K.
- Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.

## Snapshot

| | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| Provider | Moonshot AI | StepFun |
| Noometry Index | 41.2 | 47.9 |
| Rank | 140 | 58 |
| Context | 262K | 1.02M |
| Input $/M | $0.57 | $1 |
| Output $/M | $2.30 | $2.70 |
| Weights | Open | Proprietary |

## Coding

- Kimi K2 (Jul 2025): 42.4 (#102)
- Step 5 Preview: 51.8 (#36)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Coding | 1399 | 1480 |
| SWE-bench Verified (bash only) | 63.4% | — |
| Aider Polyglot | 59.1% | — |
| LMArena WebDev | — | 1564 |
| SciCode | — | 58.9% |
| GSO | 4.9% | — |
| WeirdML | 42.8% | — |
| ALE-Bench | 597.5 | — |

## Agentic & Tool Use

- Kimi K2 (Jul 2025): 32.4 (#64)
- Step 5 Preview: —

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| Terminal-Bench | 35.7% | — |
| Berkeley Function Calling Leaderboard | 59.1% | — |
| METR Time Horizons | 59.2% | — |

## Reasoning

- Kimi K2 (Jul 2025): 23.3 (#179)
- Step 5 Preview: 40.0 (#57)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Hard Prompts | 1384 | 1465 |
| SimpleBench | 26.3% | — |
| Kagi LLM Benchmark | 64.4% | — |
| CritPt | — | 20.9% |
| Epoch Capabilities Index | 146.01 | — |
| ForecastBench | 60.2 | — |

## Math

- Kimi K2 (Jul 2025): 42.7 (#83)
- Step 5 Preview: 46.1 (#72)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Math | 1397 | 1470 |
| ProofBench | — | 42% |
| Omni-MATH | 65.4% | — |
| FrontierMath (Feb 2025 set) | 21.4% | — |
| FrontierMath Tier 4 (v1) | 0% | — |

## Knowledge

- Kimi K2 (Jul 2025): 37.3 (#157)
- Step 5 Preview: 41.2 (#112)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Expert | 1365 | 1470 |
| MMLU-Pro | 81.9% | — |
| Confabulations | 20.4% | — |
| Vectara Hallucination Rate | 17.9% | — |
| GPQA (HELM) | 65.3% | — |

## Multimodal

- Kimi K2 (Jul 2025): —
- Step 5 Preview: 41.0 (#41)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Vision | — | 1267 |

## Multilingual

- Kimi K2 (Jul 2025): 49.6 (#130)
- Step 5 Preview: 53.8 (#54)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1372 | 1432 |
| LMArena Chinese | 1415 | 1519 |
| LMArena Russian | 1385 | 1436 |
| LMArena Spanish | 1386 | 1439 |
| LMArena French | 1379 | — |
| LMArena German | 1387 | — |
| LMArena Japanese | 1349 | — |
| LMArena Korean | 1325 | — |

## Instruction Following

- Kimi K2 (Jul 2025): 71.1 (#156)
- Step 5 Preview: 76.0 (#50)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1348 | 1444 |
| IFEval | 85% | — |

## Long Context

- Kimi K2 (Jul 2025): 41.2 (#145)
- Step 5 Preview: 44.5 (#64)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1353 | 1455 |
| Fiction.LiveBench | 66.7% | — |
| CL-bench | 17.6% | — |

## Writing & Preference

- Kimi K2 (Jul 2025): 62.3 (#78)
- Step 5 Preview: 62.8 (#71)

| Benchmark | Kimi K2 (Jul 2025) | Step 5 Preview |
|---|---|---|
| LMArena Text | 1380 | 1442 |
| LMArena Creative Writing | 1350 | 1410 |
| LMArena Multi-Turn | 1371 | 1447 |
| Short-Story Creative Writing | 85.6% | — |
| EQ-Bench Creative Writing | 1666 | — |
| WildBench | 86.2% | — |

## FAQ

### Is Kimi K2 (Jul 2025) better than Step 5 Preview?

Step 5 Preview is the stronger model overall, scoring 47.9 to 41.2 on the Noometry Index.

### Which is cheaper, Kimi K2 (Jul 2025) or Step 5 Preview?

Kimi K2 (Jul 2025) is cheaper. It lists at $0.57 per million input tokens and $2.30 per million output tokens; Step 5 Preview lists at $1 and $2.70.

### Is Kimi K2 (Jul 2025) or Step 5 Preview better for coding?

Step 5 Preview scores higher on coding benchmarks: 51.8 versus 42.4 in the Noometry coding category.

### Which has the bigger context window?

Step 5 Preview does, with 1.02M tokens against 262K.

### How many benchmarks do Kimi K2 (Jul 2025) and Step 5 Preview share?

13 benchmarks have published results for both models. Kimi K2 (Jul 2025) has 42 scored results on Noometry and Step 5 Preview has 18.