MoonshotAI: Kimi K3 vs SpaceXAI: Grok 4.5
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-11-12.
| MoonshotAI: Kimi K3 | SpaceXAI: Grok 4.5 | |
|---|---|---|
| Vendor | moonshotai | x-ai |
| Quality Score | 100 | 100 |
| Input Price | $0.19/M | $2.00/M |
| Output Price | $16.00/M | $6.00/M |
| Context Window | 1,048,576 | 500,000 |
| Max Output | 943,718 | 450,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, Grok 4.5 costs $3.50 and Kimi K3 costs $4.19, so Grok 4.5 is slightly cheaper for the same work.
Kimi K3 reads up to 1,048,576 tokens at once, roughly 1,573 pages of text, against about 750 pages for Grok 4.5.
Only Kimi K3 offers video input.
Across the 10 tasks where they differ, Kimi K3 scores higher on 4 (Code Completion, JSON Extraction, Bulk Data Labeling and others), Grok 4.5 on 6 (SQL Generation, Code Documentation, Regex Writing and others).
Pick Kimi K3 if you need long documents or video input; pick Grok 4.5 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 | SpaceXAI: Grok 4.5 |
|---|---|---|
| SQL Generation | 132 | 133 |
| Code Completion | 128 | 118 |
| Code Documentation | 128 | 130 |
| Regex Writing | 116 | 118 |
| CSV / Spreadsheet Cleanup | 132 | 133 |
| JSON Extraction | 128 | 122 |
| Bulk Data Labeling | 125 | 119 |
| Long-Document Summarization | 136 | 137 |
| Short-Form Summarization | 120 | 114 |
| Blog Post Writing | 120 | 121 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →