Google: Gemini 3.1 Flash Lite Preview vs Google: Gemini 3.1 Pro Preview Custom Tools
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-11-07.
| Google: Gemini 3.1 Flash Lite Preview | Google: Gemini 3.1 Pro Preview Custom Tools | |
|---|---|---|
| Vendor | ||
| Quality Score | 100 | 100 |
| Input Price | $0.25/M | $2.00/M |
| Output Price | $1.50/M | $12.00/M |
| Context Window | 1,048,576 | 1,048,576 |
| Max Output | 65,536 | 65,536 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | ✓ | ✓ |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, Gemini 3.1 Flash Lite Preview costs $0.62 and Gemini 3.1 Pro Preview Custom Tools costs $5.00, so Gemini 3.1 Flash Lite Preview is about 8.0 times cheaper for the same work.
Both read up to 1,048,576 tokens at once, roughly 1,573 pages of text.
Across the 10 tasks where they differ, Gemini 3.1 Flash Lite Preview scores higher on 10 (SQL Generation, Code Completion, Code Documentation and others).
Gemini 3.1 Flash Lite Preview was released in March 2026 and Gemini 3.1 Pro Preview Custom Tools in February 2026.
Pick Gemini 3.1 Flash Lite Preview 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 3.1 Flash Lite Preview | Google: Gemini 3.1 Pro Preview Custom Tools |
|---|---|---|
| SQL Generation | 133 | 132 |
| Code Completion | 131 | 117 |
| Code Documentation | 131 | 129 |
| Regex Writing | 119 | 117 |
| CSV / Spreadsheet Cleanup | 133 | 132 |
| JSON Extraction | 131 | 121 |
| Bulk Data Labeling | 129 | 117 |
| Long-Document Summarization | 137 | 136 |
| Short-Form Summarization | 123 | 113 |
| Blog Post Writing | 121 | 120 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →