OpenAI · Released Apr 23, 2026GPT-5.5
Default frontier GPT for coding, computer use, research, and knowledge work.
- Capability
- 159.2ECI · #10 of 148
- Input
- $5.00per 1M tokens
- Output
- $30.00per 1M tokens
- Context
- 1.05M128K max output
What it costs
- Input
- $5.00per million tokens
- Output
- $30.00per million tokens
- Cached input
- $0.50per million tokens
- Over 272K tokens
- $10.00 / $45.00input / output per million
- Blended (3:1)
- $11.25pricier than 94% of priced models
Typical monthly bills
| Monthly usage | Estimated cost |
|---|---|
| Side project2M input + 0.5M output tokens | $25.00 |
| Team assistant25M input + 5M output tokens | $275.00 |
| Production app250M input + 50M output tokens | $2,750 |
Official OpenAI API price, as listed on models.dev.
Independent benchmarks
#10 of 148 scored models
The shaded band is Epoch AI’s confidence range (156.9–162.4); 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 low · medium · high · xhigh
- Tool calling
- Yes
- Structured output
- Yes
- Weights
- Proprietary
- API model ID
gpt-5.5on OpenAI- Availability
- 42 API providerslisted on models.dev
What OpenAI claims
Published by the lab at launch. Settings vary, so compare these only with care.
| Benchmark | Score | Setting | Source |
|---|---|---|---|
| SWE-Bench Pro | 58.6 resolve rate | — | Source |
| Terminal-Bench v2.1 | 78.2 success rate | — | Source |
| SWE-Atlas Codebase QnA | 45.43 | — | Source |
| SWE-Atlas Refactoring | 44.79 | — | Source |
| SWE-Atlas Test Writing | 42.59 | — | Source |
| Artificial Analysis Coding Agent Index | 65.3 | xhigh | Source |
| SWE-Atlas Codebase QnA | 80.8 | xhigh | Source |
| SWE-Bench Pro | 30.9 | xhigh | Source |
| Terminal-Bench v2.1 | 84.1 | xhigh | Source |
| Artificial Analysis Coding Agent Index | 60.4 | medium | Source |
| SWE-Atlas Codebase QnA | 79.1 | medium | Source |
| SWE-Bench Pro | 26.2 | medium | Source |
More from OpenAI
About GPT-5.5
How much does GPT-5.5 cost?
GPT-5.5 costs $5.00 input / $30.00 output per million tokens (official OpenAI API price). Cached input is $0.50 per million tokens. Requests over 272K tokens are billed at $10.00 input / $45.00 output. At a 3:1 input-to-output mix that is $11.25 per million tokens, more expensive than 94% of the 360 priced models we track.
What is the context window of GPT-5.5?
GPT-5.5 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?
Epoch AI gives GPT-5.5 a Capabilities Index score of 159.2 (likely range 156.9–162.4), ranking it #10 of 148 models Epoch has scored. Epoch AI benchmark results: GPQA Diamond 94.0%, FrontierMath Tiers 1–3 85.3%, OTIS Mock AIME 2024–2025 100%, SWE-bench Verified 80.6%, SimpleQA Verified 63.0%.
Is GPT-5.5 open source?
No. GPT-5.5 is proprietary; you use it through OpenAI’s API or partner platforms.
What inputs does GPT-5.5 support?
GPT-5.5 accepts text, images and PDFs and replies in text. It is a reasoning model with low, medium, high and xhigh effort settings, supports tool calling and can return structured JSON output.
When was GPT-5.5 released?
OpenAI released GPT-5.5 on Apr 23, 2026. Its training data runs to Dec 1, 2025.
What are the best alternatives to GPT-5.5?
The closest current models from other labs on capability, price and release date are Claude Opus 4.8 (Anthropic, ECI 158.3, $5.00 / $25.00), Kimi K3 (Moonshot AI, ECI 157.6, $3.00 / $15.00), Gemini 3.1 Pro Preview (Google, ECI 154.8, $2.00 / $12.00) and Qwen3.8 Max (Alibaba (Qwen), ECI 156.6, $2.00 / $6.00).