# Gemini 3.1 Pro vs GPT-5.5

On provider list prices, Gemini 3.1 Pro costs $2 per million input tokens against $5 for GPT-5.5: 2.5x apart. Output is $12 against $30 (2.5x). On Allocate both bill at list plus the 7% transaction fee.

## Specifications

| | Gemini 3.1 Pro | GPT-5.5 |
| --- | --- | --- |
| Lab | Google | OpenAI |
| Access | API only | API only |
| Context window | 1M tokens | 400K tokens |
| List price, input | $2 / M tokens | $5 / M tokens |
| List price, output | $12 / M tokens | $30 / M tokens |
| Cached input | n/a | $0.50 / M tokens |
| 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 $6,600 a month on Gemini 3.1 Pro and $16,500 on GPT-5.5 at list: a gap of $9,900, or 2.5x.

Gemini 3.1 Pro reads 1M tokens per request against 400K for GPT-5.5, 2.5x the window. That decides which one can take whole documents without splitting them.

## Choose Gemini 3.1 Pro for

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

## Choose GPT-5.5 for

- Complex tool-using agents
- Code generation
- General assistants

## Common questions

### Which is cheaper, Gemini 3.1 Pro or GPT-5.5?

Gemini 3.1 Pro, on this workload shape. At list prices it is $2/$12 per million tokens in and out against $5/$30 for GPT-5.5. Billed on Allocate: $2.14/$12.84 against $5.35/$32.10, list plus 7%.

### Which has the bigger context window?

Gemini 3.1 Pro: 1,000,000 tokens (1M) against 400,000 (400K) for GPT-5.5.

### Can I fine-tune Gemini 3.1 Pro or GPT-5.5?

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/google-gemini-3-1-pro-vs-gpt-5-5) · [Gemini 3.1 Pro](https://allocate.network/models/google-gemini-3-1-pro.md) · [GPT-5.5](https://allocate.network/models/gpt-5-5.md) · [Machine-readable catalog](https://allocate.network/catalog.json)