Google: Gemini 3.6 Flash vs OpenAI: GPT-5.6 Luna Pro
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-10-22.
| Google: Gemini 3.6 Flash | OpenAI: GPT-5.6 Luna Pro | |
|---|---|---|
| Vendor | openai | |
| Quality Score | 100 | 100 |
| Input Price | $0.75/M | $0.20/M |
| Output Price | $3.75/M | $1.20/M |
| Context Window | 1,048,576 | 1,050,000 |
| Max Output | 65,536 | 128,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | ✓ | - |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, GPT-5.6 Luna Pro costs $0.50 and Gemini 3.6 Flash costs $1.69, so GPT-5.6 Luna Pro is about 3.4 times cheaper for the same work.
Both take in a similar amount of text: 1,048,576 and 1,050,000 tokens, about 1,573 and 1,575 pages.
Only Gemini 3.6 Flash offers audio input and video input.
Across the 10 tasks where they differ, GPT-5.6 Luna Pro on 10 (SQL Generation, Code Completion, Code Documentation and others).
Pick Gemini 3.6 Flash if you need audio input or video input; pick GPT-5.6 Luna Pro if you need lower cost 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 | Google: Gemini 3.6 Flash | OpenAI: GPT-5.6 Luna Pro |
|---|---|---|
| SQL Generation | 133 | 133 |
| Code Completion | 131 | 131 |
| Code Documentation | 131 | 131 |
| Regex Writing | 119 | 119 |
| CSV / Spreadsheet Cleanup | 133 | 133 |
| JSON Extraction | 131 | 131 |
| Bulk Data Labeling | 128 | 129 |
| Long-Document Summarization | 137 | 137 |
| Short-Form Summarization | 123 | 123 |
| Blog Post Writing | 121 | 121 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →