MoonshotAI: Kimi K3.1 Pro vs StepFun: Step 5 Preview
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-10-24.
| MoonshotAI: Kimi K3.1 Pro | StepFun: Step 5 Preview | |
|---|---|---|
| Vendor | moonshotai | stepfun |
| Quality Score | 100 | 100 |
| Benchmark Score | 95.1 | 73.3 |
| Input Price | $2.00/M | $1.00/M |
| Output Price | $10.00/M | $2.70/M |
| Context Window | 1,048,576 | 1,048,576 |
| Max Output | 943,718 | 64,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
| Benchmark Scores | ||
| ai_index | 90.9 | 72.2 |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, Step 5 Preview costs $1.68 and Kimi K3.1 Pro costs $4.50, so Step 5 Preview is about 2.7 times cheaper for the same work.
Both read up to 1,048,576 tokens at once, roughly 1,573 pages of text.
On our blended benchmark score Kimi K3.1 Pro leads 95.1 to 73.3.
Across the 19 tasks where they differ, Kimi K3.1 Pro scores higher on 14 (SQL Generation, Code Review, Code Refactoring and others), Step 5 Preview on 5 (Code Completion, CSV / Spreadsheet Cleanup, JSON Extraction and others).
Pick Kimi K3.1 Pro if you need benchmark performance or the stronger all-round task scores; pick Step 5 Preview if you need lower cost.
Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.
Who wins by task?
| Task | MoonshotAI: Kimi K3.1 Pro | StepFun: Step 5 Preview |
|---|---|---|
| SQL Generation | 143 | 142 |
| Code Review | 149 | 145 |
| Code Completion | 119 | 120 |
| Code Refactoring | 150 | 147 |
| Bug Fixing | 153 | 149 |
| Unit Test Generation | 134 | 132 |
| Regex Writing | 126 | 126 |
| CI/CD Pipelines | 130 | 128 |
| Frontend Component Design | 132 | 130 |
| Data Analysis | 137 | 134 |
| CSV / Spreadsheet Cleanup | 136 | 136 |
| ETL Scripting | 140 | 138 |
| JSON Extraction | 121 | 123 |
| Bulk Data Labeling | 118 | 120 |
| OCR / Document Parsing | 135 | 134 |
| Table Extraction from PDFs | 135 | 134 |
| Long-Document Summarization | 151 | 149 |
| Short-Form Summarization | 118 | 118 |
| Blog Post Writing | 131 | 130 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →