Gemini 3.1 Pro Preview vs Gemini 3.8 Flash: cost per task
Gemini 3.8 Flash is cheaper on 14 of 14 tasks and about 3.9x cheaper on average (geometric mean). On LMArena Text they are practically tied (1496 vs 1487, within the margin of error).
| Task | Gemini 3.1 Pro Preview | Gemini 3.8 Flash | Difference |
|---|---|---|---|
| Answer a chat question | 2.1¢ | 0.68¢ | 3.2x |
| Reply to a customer email | 0.97¢ | 0.25¢ | 3.9x |
| Write a 1,500-word blog post | 5.0¢ | 1.5¢ | 3.3x |
| Write 10 product descriptions | 3.9¢ | 1.2¢ | 3.2x |
| Translate 1,000 words | 11¢ | 1.9¢ | 5.6x |
| Proofread one page (500 words) | 3.6¢ | 0.51¢ | 7.0x |
| Summarize a 20-page PDF | 4.6¢ | 1.6¢ | 2.9x |
| Extract data from an invoice | 3.2¢ | 0.65¢ | 4.9x |
| Analyze a 200-row spreadsheet | 7.5¢ | 3.9¢ | 2.0x |
| Answer from 5 retrieved documents (RAG) | 3.3¢ | 1.2¢ | 2.8x |
| Classify 100 support tickets | 9.4¢ | 2.9¢ | 3.3x |
| Review 500 lines of code | 11¢ | 1.3¢ | 8.9x |
| Write a SQL query | 3.2¢ | 0.67¢ | 4.7x |
| Run a 50-step coding agent | $1.95 | 50¢ | 3.9x |
Specs and list prices
| Gemini 3.1 Pro Preview | Gemini 3.8 Flash | |
|---|---|---|
| Input per 1M | $2.00 | $0.82 |
| Output per 1M | $12.00 | $4.12 |
| Cached input per 1M | $0.20 | $0.083 |
| Context | 1M | 1M |
| Providers | 6 | 7 |
| Reasoning | always | always |
| LMArena Text | 1487 | 1496 |
| Released | Feb 19, 2026 | Sep 2, 2026 |
FAQ
Is Gemini 3.1 Pro Preview or Gemini 3.8 Flash cheaper?
Gemini 3.8 Flash is cheaper on 14 of 14 tasks and about 3.9x cheaper on average (geometric mean). On LMArena Text they are practically tied (1496 vs 1487, within the margin of error).
How much does Gemini 3.1 Pro Preview cost compared to Gemini 3.8 Flash per token?
Gemini 3.1 Pro Preview: $2.00 input and $12.00 output per 1M tokens. Gemini 3.8 Flash: $0.82 input and $4.12 output. Token prices alone mislead - models use different numbers of tokens for the same task, which is what the task table shows.