Gemini 3.1 Pro Preview vs Gemini 3.5 Flash: API pricing comparison
Google Gemini 3.1 Pro Preview vs Google Gemini 3.5 Flash: token prices, batch and cache rates, Arena ELO, and cost per request for 8 business use cases. Prices in USD per 1 million tokens. Data snapshot: 2026-11-12.
Gemini 3.1 Pro Preview vs Gemini 3.5 Flash: the short version
At the prices we quote, Gemini 3.5 Flash costs less than Gemini 3.1 Pro Preview on input and on output: $1.50 against $2.00 per 1M input tokens (25% less), and $9.00 against $12.00 per 1M output tokens (25% less). With the Support Ticket profile (1,500 input and 500 output tokens per request), 1,000 requests cost $9.00 on Gemini 3.1 Pro Preview and $6.75 on Gemini 3.5 Flash at list price, 25% less on Gemini 3.5 Flash. On Arena ELO, Gemini 3.5 Flash scores 1483 and Gemini 3.1 Pro Preview scores 1480, 3 points apart (scores as of 2026-11-08). The context window is 1M tokens on both. Both are recorded here as proprietary, with access through an API. Prices as quoted on 2026-11-12. Each price is the list price of one host, the one we quote for that model. A model sold by several hosts has other prices, listed on its model page.
Gemini 3.1 Pro Preview pricing (Google)
- Input: $2.00 per 1M tokens
- Output: $12.00 per 1M tokens
- Batch API (input/output): $1.00 / $6.00
- Prompt-cache read: $0.20
- Context window: 1M
- Arena ELO: 1480 (as of 2026-11-08)
- Full Gemini 3.1 Pro Preview pricing page
Gemini 3.5 Flash pricing (Google)
- Input: $1.50 per 1M tokens
- Output: $9.00 per 1M tokens
- Batch API (input/output): $0.75 / $4.50
- Prompt-cache read: $0.15
- Context window: 1M
- Arena ELO: 1483 (as of 2026-11-08)
- Full Gemini 3.5 Flash pricing page
Cost per 1,000 requests by business use case
List price vs after discounts (prompt caching on the cached input share, batch API for async workloads, only where the provider publishes those rates).
| Use case | Tokens (in/out) | Gemini 3.1 Pro Preview list price | Gemini 3.1 Pro Preview after discounts | Gemini 3.5 Flash list price | Gemini 3.5 Flash after discounts |
|---|---|---|---|---|---|
| Support Ticket | 1,500 / 500 | $9.00 | $7.38 | $6.75 | $5.54 |
| Knowledge Q&A | 2,000 / 800 | $13.60 | $11.08 | $10.20 | $8.31 |
| Meeting Summary | 10,000 / 1,200 | $34.40 | $16.40 | $25.80 | $12.30 |
| Marketing Content | 2,500 / 1,800 | $26.60 | $25.70 | $19.95 | $19.28 |
| Coding Task | 3,000 / 2,000 | $30.00 | $27.30 | $22.50 | $20.48 |
| Invoice Processing | 1,500 / 600 | $10.20 | $4.74 | $7.65 | $3.55 |
| Call Summary | 2,000 / 700 | $12.40 | $6.04 | $9.30 | $4.53 |
| Agent Workflow | 6,000 / 3,000 | $48.00 | $40.44 | $36.00 | $30.33 |
Common questions about Gemini 3.1 Pro Preview vs Gemini 3.5 Flash
- Which is cheaper, Gemini 3.1 Pro Preview or Gemini 3.5 Flash?
- At the prices we quote, Gemini 3.5 Flash costs less than Gemini 3.1 Pro Preview on input and on output: $1.50 against $2.00 per 1M input tokens (25% less), and $9.00 against $12.00 per 1M output tokens (25% less). Prices as quoted on 2026-11-12. Each price is the list price of one host, the one we quote for that model. A model sold by several hosts has other prices, listed on its model page.
- What do 1,000 Support Ticket requests cost on Gemini 3.1 Pro Preview and on Gemini 3.5 Flash?
- With the Support Ticket profile (1,500 input and 500 output tokens per request), 1,000 requests cost $9.00 on Gemini 3.1 Pro Preview and $6.75 on Gemini 3.5 Flash at list price, 25% less on Gemini 3.5 Flash. Prices as quoted on 2026-11-12.
- How do Gemini 3.1 Pro Preview and Gemini 3.5 Flash compare on Arena score, context window and licence?
- On Arena ELO, Gemini 3.5 Flash scores 1483 and Gemini 3.1 Pro Preview scores 1480, 3 points apart (scores as of 2026-11-08). The context window is 1M tokens on both. Both are recorded here as proprietary, with access through an API.
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These are list prices: real cost also depends on caching, batching, negotiated discounts, marketplace agreements, and existing contracts. Get a FinOps review from OptimNow or compare all models.