Model comparison
Kimi K2.5 vs Step 5 Preview
Kimi K2.5 and Step 5 Preview score almost the same on the Noometry Index (48.1 vs 47.9), so choose on price, context window or the category you care about most.
Last verified . 17 shared benchmarks.
StepFunSummary
- They share 17 benchmarks with published results for both. Kimi K2.5 scores higher in 6 categories and Step 5 Preview in 3 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Kimi K2.5 leads 53.6 to 41.2.
- The biggest single-benchmark swing is CritPt: 3.1% for Kimi K2.5 and 20.9% for Step 5 Preview.
- Kimi K2.5 is cheaper at $0.45 / $2.25 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 K2.5 has downloadable open weights; the other is API-only.
Side by side
| Kimi K2.5 | Step 5 Preview | |
|---|---|---|
| Provider | Moonshot AI | StepFun |
| Noometry Index | 48.1 | 47.9 |
| Released | 2026-01-27 | 2026-09-16 |
| Weights | Open | Proprietary |
| Context window | 262K | 1.02M |
| Max output | 262K | 66K |
| Input $ / M tokens | $0.45 | $1 |
| Output $ / M tokens | $2.25 | $2.70 |
| Results tracked | 51 | 18 |
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Category by category
Coding Step 5 Preview leads
Kimi K2.5: 48.8 (#53), Step 5 Preview: 51.8 (#36)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena WebDev | 1437 | 1564 |
| SciCode | 49% | 58.9% |
| LMArena Coding | 1474 | 1480 |
| SWE-bench Verified | 73.8% | — |
| SWE-bench Verified (bash only) | 70.8% | — |
| SWE-bench Multilingual | 67.3% | — |
| WeirdML | 45.6% | — |
| ALE-Bench | 821.65 | — |
Agentic & Tool Use Not comparable
Kimi K2.5: 34.2 (#48), Step 5 Preview: —
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| Terminal-Bench | 43.2% | — |
| OSWorld | 63.3% | — |
| Vending-Bench 2 | 1,198 | — |
Reasoning Step 5 Preview leads
Kimi K2.5: 31.2 (#80), Step 5 Preview: 40.0 (#57)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| CritPt | 3.1% | 20.9% |
| LMArena Hard Prompts | 1453 | 1465 |
| ARC-AGI-2 | 11.8% | — |
| SimpleBench | 46.8% | — |
| Kagi LLM Benchmark | 78.5% | — |
| NYT Connections (extended) | 69.9% | — |
| ARC-AGI-1 | 65.3% | — |
| Chess Puzzles | 12% | — |
| EnigmaEval | 3.4% | — |
| Thematic Generalization | 69.4% | — |
| Epoch Capabilities Index | 148.03 | — |
Math Kimi K2.5 leads
Kimi K2.5: 51.8 (#53), Step 5 Preview: 46.1 (#72)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena Math | 1470 | 1470 |
| MathArena Final-Answer Competitions | 62.3% | — |
| OTIS Mock AIME 2024-2025 | 92.2% | — |
| ProofBench | — | 42% |
| FrontierMath (Feb 2025 set) | 27.9% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Kimi K2.5 leads
Kimi K2.5: 53.6 (#56), Step 5 Preview: 41.2 (#112)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena Expert | 1466 | 1470 |
| GPQA Diamond | 87.6% | — |
| Humanity's Last Exam | 24.4% | — |
| SimpleQA Verified | 34.3% | — |
| Vectara Hallucination Rate | 14.2% | — |
Multimodal Too close to call
Kimi K2.5: 41.1 (#39), Step 5 Preview: 41.0 (#41)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena Vision | 1269 | 1267 |
| LMArena Document | 1430 | — |
Multilingual Too close to call
Kimi K2.5: 53.9 (#53), Step 5 Preview: 53.8 (#54)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1433 | 1432 |
| LMArena Chinese | 1495 | 1519 |
| LMArena Russian | 1435 | 1436 |
| LMArena Spanish | 1450 | 1439 |
| LMArena French | 1454 | — |
| LMArena German | 1441 | — |
| LMArena Japanese | 1421 | — |
| LMArena Korean | 1410 | — |
Instruction Following Too close to call
Kimi K2.5: 75.3 (#64), Step 5 Preview: 76.0 (#50)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1431 | 1444 |
Long Context Kimi K2.5 leads
Kimi K2.5: 52.1 (#7), Step 5 Preview: 44.5 (#64)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1445 | 1455 |
| Fiction.LiveBench | 86.1% | — |
| CL-bench | 19.3% | — |
| CL-bench Life | 13.2% | — |
Writing & Preference Kimi K2.5 leads
Kimi K2.5: 65.1 (#53), Step 5 Preview: 62.8 (#71)
| Benchmark | Kimi K2.5 | Step 5 Preview |
|---|---|---|
| LMArena Text | 1445 | 1442 |
| LMArena Creative Writing | 1423 | 1410 |
| LMArena Multi-Turn | 1444 | 1447 |
| EQ-Bench Creative Writing | 1579 | — |
Frequently asked questions
Is Kimi K2.5 better than Step 5 Preview?
Kimi K2.5 and Step 5 Preview score almost the same on the Noometry Index (48.1 vs 47.9), so choose on price, context window or the category you care about most.
Which is cheaper, Kimi K2.5 or Step 5 Preview?
Kimi K2.5 is cheaper. It lists at $0.45 per million input tokens and $2.25 per million output tokens; Step 5 Preview lists at $1 and $2.70.
Is Kimi K2.5 or Step 5 Preview better for coding?
Step 5 Preview scores higher on coding benchmarks: 51.8 versus 48.8 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 K2.5 and Step 5 Preview share?
17 benchmarks have published results for both models. Kimi K2.5 has 51 scored results on Noometry and Step 5 Preview has 18.