MoonshotAI: Kimi K3 vs Anthropic: Claude Sonnet 5
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-09-27.
| MoonshotAI: Kimi K3 | Anthropic: Claude Sonnet 5 | |
|---|---|---|
| Vendor | moonshotai | anthropic |
| Quality Score | 100 | 100 |
| Benchmark Score | 73.9 | 63.9 |
| Input Price | $3.00/M | $2.00/M |
| Output Price | $15.00/M | $10.00/M |
| Context Window | 1,048,576 | 1,000,000 |
| Max Output | 943,718 | 128,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
| Benchmark Scores | ||
| ai_index | 71.9 | 63.0 |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, Claude Sonnet 5 costs $4.50 and Kimi K3 costs $6.75, so Claude Sonnet 5 is about 1.5 times cheaper for the same work.
Both take in a similar amount of text: 1,048,576 and 1,000,000 tokens, about 1,573 and 1,500 pages.
Only Kimi K3 offers video input.
On our blended benchmark score Kimi K3 leads 73.9 to 63.9.
Across the 20 tasks where they differ, Kimi K3 scores higher on 13 (SQL Generation, Code Review, Code Refactoring and others), Claude Sonnet 5 on 7 (Code Completion, Code Documentation, Regex Writing and others).
Kimi K3 was released in July 2026 and Claude Sonnet 5 in June 2026.
Pick Kimi K3 if you need video input or benchmark performance; pick Claude Sonnet 5 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 | Anthropic: Claude Sonnet 5 |
|---|---|---|
| SQL Generation | 140 | 140 |
| Code Review | 145 | 144 |
| Code Completion | 117 | 118 |
| Code Refactoring | 147 | 146 |
| Bug Fixing | 149 | 148 |
| Unit Test Generation | 132 | 131 |
| Code Documentation | 134 | 135 |
| Regex Writing | 123 | 123 |
| CI/CD Pipelines | 128 | 127 |
| Frontend Component Design | 130 | 129 |
| Data Analysis | 134 | 133 |
| CSV / Spreadsheet Cleanup | 135 | 135 |
| ETL Scripting | 138 | 136 |
| JSON Extraction | 120 | 121 |
| Bulk Data Labeling | 116 | 118 |
| OCR / Document Parsing | 134 | 134 |
| Table Extraction from PDFs | 134 | 134 |
| Long-Document Summarization | 147 | 146 |
| Short-Form Summarization | 116 | 116 |
| Blog Post Writing | 128 | 128 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →