OpenAI: GPT-6 Luna Pro (batch) vs Z.ai: GLM 5.3 Flash
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-11-07.
| OpenAI: GPT-6 Luna Pro (batch) | Z.ai: GLM 5.3 Flash | |
|---|---|---|
| Vendor | openai | z-ai |
| Quality Score | 100 | 100 |
| Input Price | $0.05/M | $0.03/M |
| Output Price | $0.25/M | $0.08/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, GLM 5.3 Flash costs $0.054 and GPT-6 Luna Pro (batch) costs $0.11, so GLM 5.3 Flash is about 2.1 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 Flash offers video input.
Across the 6 tasks where they differ, GLM 5.3 Flash on 6 (Code Completion, Code Documentation, Regex Writing and others).
GPT-6 Luna Pro (batch) was released in September 2026 and GLM 5.3 Flash in August 2026.
Pick GLM 5.3 Flash if you need lower cost, video input or the stronger all-round task scores.
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 Flash |
|---|---|---|
| Code Completion | 131 | 132 |
| Code Documentation | 131 | 132 |
| Regex Writing | 119 | 120 |
| JSON Extraction | 131 | 132 |
| Bulk Data Labeling | 129 | 130 |
| Short-Form Summarization | 123 | 124 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →