AI model comparison
Step 5 Preview vs Kimi K3
Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.
StepFun
Step 5 Preview
Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters).
- Input / 1M
- $1
- Output / 1M
- $2.70
- Context
- 1.05M
Moonshot AI
Kimi K3
Kimi K3 is a 2.8T parameter open-weight multimodal reasoning model from Moonshot AI.
- Input / 1M
- $0.45
- Output / 1M
- $15
- Context
- 1.05M
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
Step 5 Preview
2.5x cheaper for a typical chat
Higher intelligence score
Step 5 Preview
43.7 vs 43.6 on Artificial Analysis
Larger context window
Tie
1.05M vs 1.05M tokens
Newer release
Step 5 Preview
Released October 8, 2026
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
Coding index
Agentic index
Pricing
Step 5 Preview vs Kimi K3 API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | ||
|---|---|---|
| Input tokensPer 1M tokens | $1 | $0.45 |
| Output tokensPer 1M tokens | $2.70 | $15 |
| Cached input (read)Per 1M tokens | $0.05 | $0.28 |
| Cache writePer 1M tokens | Not available | Not available |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
Coding task
30K in, 4K out
Long document summary
150K in, 2K out
Specs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | ||
|---|---|---|
| Context window | 1.05M tokens | 1.05M tokens |
| Max output | 64K tokens | 944K tokens |
| Input types | Image, Text, Video | Image, Text, Video |
| Output types | Text | Text |
| Reasoning effort levels | High, Medium, Low | Max, High, Low |
| Default reasoning effort | Medium | Max |
| Release date | October 8, 2026 | July 16, 2026 |
Features
Supported features
API features available for each model.
| Metric | ||
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Supported | Supported |
| Stop sequences | Supported | Supported |
| Deterministic seed | Supported | Supported |
| Verbosity control | Not supported | Not supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
- Step 5 Preview vs DeepSeek V4.1 Flash
- Step 5 Preview vs GLM 5.3 Flash
- Step 5 Preview vs MiMo-V2.6-Flash
- Step 5 Preview vs Hy4 preview
- Step 5 Preview vs GPT-6 Luna
- Step 5 Preview vs Claude Opus 5.5
- Step 5 Preview vs DeepSeek V4 Flash 0731
- Step 5 Preview vs GLM 5.3
- Step 5 Preview vs Hy3
- Step 5 Preview vs DeepSeek V4 Flash 0423
- Step 5 Preview vs Muse Spark 1.3 Contributor
- Step 5 Preview vs Claude Sonnet 5.5
- Step 5 Preview vs GPT-6.1 Sol
- Step 5 Preview vs Claude Haiku 5.5
- Step 5 Preview vs Claude Fable 5.1
- Step 5 Preview vs Gemini 3.8 Flash
- Step 5 Preview vs GPT-6 Astra
- Step 5 Preview vs GPT-5.6 Luna
- Step 5 Preview vs Gemini 4 Argon
- Step 5 Preview vs MiMo-V2.6-Pro
- Step 5 Preview vs DeepSeek V4 Pro 0813
- Step 5 Preview vs Muse Spark 1.3
- Step 5 Preview vs GPT-6 Sol
- Step 5 Preview vs GPT-5.6 Sol
- Step 5 Preview vs Grok 4.7
- Step 5 Preview vs Qwen3.8 Max (0902)
- Step 5 Preview vs Grok 4.6
- Step 5 Preview vs Claude Sonnet 5
- Step 5 Preview vs GPT-5.6 Terra
- Step 5 Preview vs Claude Opus 4.8
- Step 5 Preview vs Ling 3.1 Flash
- Step 5 Preview vs Claude Opus 4.7
- Step 5 Preview vs Qwen3.8 2.4T A95B
- Step 5 Preview vs Gemini 3.7 Flash
- Step 5 Preview vs Muse Spark 1.2
- Step 5 Preview vs Grok 4.5
- Step 5 Preview vs Qwen3.8 27B
- Step 5 Preview vs Mistral Large 4
- Step 5 Preview vs Muse Spark 1.1
- Step 5 Preview vs GLM 5.3 FlashX
- Step 5 Preview vs GPT-5.6 Luna Pro
- Kimi K3 vs Claude Opus 5.5
- Kimi K3 vs GPT-6 Astra
- Kimi K3 vs GLM 5.3
- Kimi K3 vs Claude Fable 5
- Kimi K3 vs GPT-6 Sol
- Kimi K3 vs GPT-5.6 Sol
- Kimi K3 vs Grok 4.7
- Kimi K3 vs Qwen3.8 Max (0902)
- Kimi K3 vs Gemini 3.8 Flash
- Kimi K3 vs Grok 4.6
- Kimi K3 vs GPT-5.6 Terra
- Kimi K3 vs Claude Opus 4.8
- Kimi K3 vs Claude Opus 4.7
- Kimi K3 vs Qwen3.8 2.4T A95B
- Kimi K3 vs Claude Sonnet 5
- Kimi K3 vs GPT-5.4
- Kimi K3 vs GPT-5.5
Our take
Step 5 Preview is 2.5x cheaper for a typical chat. Step 5 Preview scores higher on the Artificial Analysis Intelligence Index (43.7 vs 43.6). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.
FAQ
Frequently asked questions
Is Step 5 Preview or Kimi K3 cheaper?
Step 5 Preview is cheaper for a typical chat (2K input tokens and 500 output tokens). Step 5 Preview costs $1 per 1M input tokens and $2.70 per 1M output tokens, while Kimi K3 costs $0.45 per 1M input tokens and $15 per 1M output tokens.
Which has a bigger context window, Step 5 Preview or Kimi K3?
Step 5 Preview supports up to 1.05M tokens of context, compared with 1.05M for Kimi K3.
Is Step 5 Preview smarter than Kimi K3?
On the Artificial Analysis Intelligence Index, Step 5 Preview scores 43.7 and Kimi K3 scores 43.6, putting Step 5 Preview ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.
Can I use Step 5 Preview and Kimi K3 at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Step 5 Preview and Kimi K3 answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to Step 5 Preview and Kimi K3 at the same time. Compare the answers side by side and keep the best one.