Gemini 3.1 Pro Preview vs Gemini 3.5 Flash Lite: cost per task
Gemini 3.5 Flash Lite is cheaper on 14 of 14 tasks and about 7.0x cheaper on average (geometric mean). Gemini 3.1 Pro Preview has the higher LMArena Text score (1487 vs 1455).
| Task | Gemini 3.1 Pro Preview | Gemini 3.5 Flash Lite | Difference |
|---|---|---|---|
| Answer a chat question | 2.1¢ | 0.41¢ | 5.2x |
| Reply to a customer email | 0.97¢ | 0.15¢ | 6.7x |
| Write a 1,500-word blog post | 5.0¢ | 0.90¢ | 5.5x |
| Write 10 product descriptions | 3.9¢ | 0.74¢ | 5.3x |
| Translate 1,000 words | 11¢ | 1.2¢ | 9.4x |
| Proofread one page (500 words) | 3.6¢ | 0.30¢ | 12.1x |
| Summarize a 20-page PDF | 4.6¢ | 0.69¢ | 6.6x |
| Extract data from an invoice | 3.2¢ | 0.38¢ | 8.3x |
| Analyze a 200-row spreadsheet | 7.5¢ | 2.2¢ | 3.4x |
| Answer from 5 retrieved documents (RAG) | 3.3¢ | 0.65¢ | 5.1x |
| Classify 100 support tickets | 9.4¢ | 1.7¢ | 5.6x |
| Review 500 lines of code | 11¢ | 0.67¢ | 16.9x |
| Write a SQL query | 3.2¢ | 0.40¢ | 7.9x |
| Run a 50-step coding agent | $1.95 | 24¢ | 8.1x |
Specs and list prices
| Gemini 3.1 Pro Preview | Gemini 3.5 Flash Lite | |
|---|---|---|
| Input per 1M | $2.00 | $0.30 |
| Output per 1M | $12.00 | $2.50 |
| Cached input per 1M | $0.20 | $0.03 |
| Context | 1M | 1M |
| Providers | 6 | 8 |
| Reasoning | always | always |
| LMArena Text | 1487 | 1455 |
| Released | Feb 19, 2026 | Jul 21, 2026 |
FAQ
Is Gemini 3.1 Pro Preview or Gemini 3.5 Flash Lite cheaper?
Gemini 3.5 Flash Lite is cheaper on 14 of 14 tasks and about 7.0x cheaper on average (geometric mean). Gemini 3.1 Pro Preview has the higher LMArena Text score (1487 vs 1455).
How much does Gemini 3.1 Pro Preview cost compared to Gemini 3.5 Flash Lite per token?
Gemini 3.1 Pro Preview: $2.00 input and $12.00 output per 1M tokens. Gemini 3.5 Flash Lite: $0.30 input and $2.50 output. Token prices alone mislead - models use different numbers of tokens for the same task, which is what the task table shows.