OpenAI · Released Apr 23, 2026GPT-5.5 Pro
Highest-accuracy GPT-5.5 tier for slower, precision-heavy reasoning and coding.
- Capability
- 162.4ECI · #6 of 148
- Input
- $30.00per 1M tokens
- Output
- $180.00per 1M tokens
- Context
- 1.05M128K max output
What it costs
- Input
- $30.00per million tokens
- Output
- $180.00per million tokens
- Over 272K tokens
- $60.00 / $270.00input / output per million
- Blended (3:1)
- $67.50pricier than 99% of priced models
Typical monthly bills
| Monthly usage | Estimated cost |
|---|---|
| Side project2M input + 0.5M output tokens | $150.00 |
| Team assistant25M input + 5M output tokens | $1,650 |
| Production app250M input + 50M output tokens | $16,500 |
Official OpenAI API price, as listed on models.dev.
Independent benchmarks
#6 of 148 scored models
The shaded band is Epoch AI’s confidence range (159.0–166.0); the tick marks the median scored model.
Scores from Epoch AI, run independently of OpenAI.
The details
- Lab
- OpenAI
- Released
- Apr 23, 2026
- Knowledge cutoff
- Dec 1, 2025
- Context window
- 1,050,000 tokens
- Max output
- 128,000 tokens
- Inputs
- Text, Images, PDFs
- Output
- Text
- Reasoning
- Adjustable effort medium · high · xhigh
- Tool calling
- Yes
- Structured output
- Yes
- Weights
- Proprietary
- API model ID
gpt-5.5-proon OpenAI- Availability
- 19 API providerslisted on models.dev
What OpenAI claims
Published by the lab at launch. Settings vary, so compare these only with care.
More from OpenAI
About GPT-5.5 Pro
How much does GPT-5.5 Pro cost?
GPT-5.5 Pro costs $30.00 input / $180.00 output per million tokens (official OpenAI API price). Requests over 272K tokens are billed at $60.00 input / $270.00 output. At a 3:1 input-to-output mix that is $67.50 per million tokens, more expensive than 99% of the 360 priced models we track.
What is the context window of GPT-5.5 Pro?
GPT-5.5 Pro accepts up to 1,050,000 tokens per request and can write up to 128,000 tokens in one response.
How good is GPT-5.5 Pro?
Epoch AI gives GPT-5.5 Pro a Capabilities Index score of 162.4 (likely range 159.0–166.0), ranking it #6 of 148 models Epoch has scored. Epoch AI benchmark results: GPQA Diamond 93.9%, FrontierMath Tiers 1–3 87.7%, OTIS Mock AIME 2024–2025 100%.
Is GPT-5.5 Pro open source?
No. GPT-5.5 Pro is proprietary; you use it through OpenAI’s API or partner platforms.
What inputs does GPT-5.5 Pro support?
GPT-5.5 Pro accepts text, images and PDFs and replies in text. It is a reasoning model with medium, high and xhigh effort settings, supports tool calling and can return structured JSON output.
When was GPT-5.5 Pro released?
OpenAI released GPT-5.5 Pro on Apr 23, 2026. Its training data runs to Dec 1, 2025.
What are the best alternatives to GPT-5.5 Pro?
The closest current models from other labs on capability, price and release date are Claude Fable 5 (Anthropic, ECI 162.2, $10.00 / $50.00), Kimi K3 (Moonshot AI, ECI 157.6, $3.00 / $15.00), Grok 4.7 (xAI, $2.00 / $6.00) and Laguna XS.2 (Poolside).