# GPT-5.5

GPT-5.5 is a language model from OpenAI with a 400K-token context window. Provider list price is $5 per million input tokens and $30 per million output; on Allocate you pay $5.35 and $32.10. It is a closed model served over API; the weights are not published.

## Pricing

| | Provider list | On Allocate |
| --- | --- | --- |
| Input, per M tokens | $5 | $5.35 |
| Output, per M tokens | $30 | $32.10 |
| Cached input, per M tokens | $0.50 | $0.54 |

Prices checked 2026-07-21.

## Facts

| Field | Value |
| --- | --- |
| Lab | OpenAI |
| Modality | Language |
| Context window | 400K tokens |
| License | Proprietary API |
| Open weights | No |
| Fine-tunable | No |
| Catalog id | openai/gpt-5.5 |

## What a real workload costs

Take 1,000,000 requests a month at 1,200 input and 350 output tokens each: 1,200M input and 350M output tokens. At list prices that is 1,200 × $5 + 350 × $30 = $16,500 a month. Billed on Allocate it is $17,655.

## Where it fits

OpenAI’s broad-capability flagship with 400K context and best-in-class tool use. Strong at long agentic sequences where reliability of function calls matters more than raw speed.

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

## Common questions

### How much does GPT-5.5 cost per million tokens?

Provider list price is $5 per million input tokens and $30 per million output tokens. On Allocate you pay $5.35 in and $32.10 out.

### What context window does GPT-5.5 have?

400,000 tokens (400K). At roughly 0.75 words per token, that is about 300k words of English text per request.

### What does cached input cost on GPT-5.5?

$0.50 per million tokens at list ($0.54 billed). Repeated prompt prefixes, such as a stable system prompt or tool definitions, bill at this rate instead of the full input price.

### Can I fine-tune GPT-5.5?

No. GPT-5.5 is a closed model served over API; the weights are not published. If you want a model you can train and own, start from an open-weights base in the catalog and fine-tune that.

### How do I call GPT-5.5 on Allocate?

Send openai/gpt-5.5 in the model field of the OpenAI-compatible endpoint at api.allocate.network/v1, or point a route name (like prod/support-agent) at it so you can swap the model later without a deploy.

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[HTML page](https://allocate.network/models/gpt-5-5) · [Machine-readable catalog](https://allocate.network/catalog.json)