# Gemini 3.5 Flash vs Gemini 3.1 Pro

On provider list prices, Gemini 3.5 Flash costs $1.50 per million input tokens against $2 for Gemini 3.1 Pro: 1.3x apart. Output is $9 against $12 (1.3x). On Allocate both bill at list plus the 7% transaction fee.

## Specifications

| | Gemini 3.5 Flash | Gemini 3.1 Pro |
| --- | --- | --- |
| Lab | Google | Google |
| Access | API only | API only |
| Context window | 1M tokens | 1M tokens |
| List price, input | $1.50 / M tokens | $2 / M tokens |
| List price, output | $9 / M tokens | $12 / M tokens |
| Cached input | n/a | n/a |
| License | Proprietary API | Proprietary API |
| Fine-tunable | No | No |

Specifications and provider list prices from the Allocate catalog, checked 2026-07-08. Billed price is list plus the 7% transaction fee.

## What the numbers say

Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $4,950 a month on Gemini 3.5 Flash and $6,600 on Gemini 3.1 Pro at list: a gap of $1,650, or 1.3x.

## Choose Gemini 3.5 Flash for

- High-volume support and triage
- Document extraction at scale
- Vision and OCR pipelines

## Choose Gemini 3.1 Pro for

- Judgment-heavy workflows
- Long-context analysis
- Escalation tier above Flash

## Common questions

### Which is cheaper, Gemini 3.5 Flash or Gemini 3.1 Pro?

Gemini 3.5 Flash, on this workload shape. At list prices it is $1.50/$9 per million tokens in and out against $2/$12 for Gemini 3.1 Pro. Billed on Allocate: $1.60/$9.63 against $2.14/$12.84, list plus 7%.

### Which has the bigger context window?

They match: both read 1,000,000 tokens (1M) per request.

### Can I fine-tune Gemini 3.5 Flash or Gemini 3.1 Pro?

No. Both are closed models served over API. If you want a model you can train and own, start from an open-weights base in the catalog.

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[HTML page](https://allocate.network/compare/gemini-3-5-flash-vs-google-gemini-3-1-pro) · [Gemini 3.5 Flash](https://allocate.network/models/gemini-3-5-flash.md) · [Gemini 3.1 Pro](https://allocate.network/models/google-gemini-3-1-pro.md) · [Machine-readable catalog](https://allocate.network/catalog.json)