OpenAI: GPT-6 Luna Pro (batch) vs Z.ai: GLM 5.3 FlashX
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-10-13.
| OpenAI: GPT-6 Luna Pro (batch) | Z.ai: GLM 5.3 FlashX | |
|---|---|---|
| Vendor | openai | z-ai |
| Quality Score | 100 | 100 |
| Input Price | $0.05/M | $0.37/M |
| Output Price | $0.25/M | $1.25/M |
| Context Window | 1,050,000 | 1,048,576 |
| Max Output | 128,000 | 131,072 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, GPT-6 Luna Pro (batch) costs $0.11 and GLM 5.3 FlashX costs $0.68, so GPT-6 Luna Pro (batch) is about 6.1 times cheaper for the same work.
Both take in a similar amount of text: 1,050,000 and 1,048,576 tokens, about 1,575 and 1,573 pages.
Only GLM 5.3 FlashX offers video input.
Across the 10 tasks where they differ, GPT-6 Luna Pro (batch) scores higher on 10 (SQL Generation, Code Completion, Code Documentation and others).
Pick GPT-6 Luna Pro (batch) if you need lower cost or the stronger all-round task scores; pick GLM 5.3 FlashX if you need video input.
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 | OpenAI: GPT-6 Luna Pro (batch) | Z.ai: GLM 5.3 FlashX |
|---|---|---|
| SQL Generation | 134 | 133 |
| Code Completion | 131 | 131 |
| Code Documentation | 131 | 131 |
| Regex Writing | 119 | 119 |
| CSV / Spreadsheet Cleanup | 134 | 133 |
| JSON Extraction | 131 | 131 |
| Bulk Data Labeling | 129 | 129 |
| Long-Document Summarization | 138 | 137 |
| Short-Form Summarization | 123 | 123 |
| Blog Post Writing | 122 | 121 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →