AI Model Atlas / OpenAI
GPT-5.5 Pro
One million input tokens cost $30.00 and one million output tokens $180.00. Context window: 1.1M tokens, about 1,750 A4 pages.
What it costs in practice
Pricing per million tokens doesn't mean anything to anyone, so I convert it to three tasks that people actually give to models. The usage assumptions are listed for each row so you can verify them.
| Task | Input | Output | Cost |
|---|---|---|---|
| 1500-word articlebrief plus finished text in English | 1,500 tokens | 2,200 tokens | $0.44 |
| 100 chat queries700 tokens per question and 400 per answer | 70,000 tokens | 40,000 tokens | $9.30 |
| Hour of work with an agentagent reads repository and writes fixes | 250,000 tokens | 30,000 tokens | $12.90 |
Technical details
| Provider | OpenAI |
| Modalities | files + image + text → text |
| Context window | 1.1M tokens (~1,750 A4 pages) |
| Maximum response | 128k tokens |
| Step-by-step reasoning | yes |
| Tool calling | yes |
| Forced JSON format | yes |
| Knowledge cutoff | 2025-12-01 |
| Cache read | no data |
| Content moderation | yes, provider filters |
How it compares to the rest
The database contains 469 models. In terms of input pricing GPT-5.5 Pro is more expensive than 99 percent of paid models. A longer context window is available in 7 models.
Input price history
2026-09-08 · $30.002026-11-11 · $30.00
The chart shows the price of a million input tokens on consecutive measurement days. History starts on the day I launched the atlas and grows with each day. I don't backfill data.
Alternatives at a similar price
Models from other providers whose cost for the same article comes out closest.
| Model | Input / M | Output / M | 1500-word article | Context |
|---|---|---|---|---|
| Claude Opus 4.1Anthropic | $15.00 | $75.00 | $0.19 | 200k |
| Claude Fable 5.1Anthropic | $10.00 | $50.00 | $0.13 | 1M |
| Claude Fable 5Anthropic | $10.00 | $50.00 | $0.13 | 1M |
| Claude Fable 5.2Anthropic | $8.00 | $40.00 | $0.10 | 1M |
Compare GPT-5.5 Pro with another model or go back to the full database 469 models.