# Gemini 3.5 Flash vs GPT-5.5

On provider list prices, Gemini 3.5 Flash costs $1.50 per million input tokens against $5 for GPT-5.5: 3.3x apart. Output is $9 against $30 (3.3x).

## Specifications

| | Gemini 3.5 Flash | GPT-5.5 |
| --- | --- | --- |
| Lab | Google | OpenAI |
| Access | API only | API only |
| Context window | 1M tokens | 400K tokens |
| List price, input | $1.50 / M tokens | $5 / M tokens |
| List price, output | $9 / 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 2026-07-21.

## 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 $16,500 on GPT-5.5 at list: a gap of $11,550, or 3.3x.

Gemini 3.5 Flash 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 3.5 Flash for

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

## Choose GPT-5.5 for

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

## Common questions

### Which is cheaper, Gemini 3.5 Flash or GPT-5.5?

Gemini 3.5 Flash, on this workload shape. At list prices it is $1.50/$9 per million tokens in and out against $5/$30 for GPT-5.5. Billed on Allocate: $1.60/$9.63 against $5.35/$32.10.

### Which has the bigger context window?

Gemini 3.5 Flash: 1,000,000 tokens (1M) against 400,000 (400K) for GPT-5.5.

### Can I fine-tune Gemini 3.5 Flash 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/gemini-3-5-flash-vs-gpt-5-5) · [Gemini 3.5 Flash](https://allocate.network/models/gemini-3-5-flash.md) · [GPT-5.5](https://allocate.network/models/gpt-5-5.md) · [Machine-readable catalog](https://allocate.network/catalog.json)