GPT-5 vs GPT-5.5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
GPT-5
70.7OpenAI · Aug 2025
OpenAI's August 2025 unified flagship that merged the GPT and o-series reasoning lines into one model with selectable effort.
GPT-5.5
77.2OpenAI · Apr 2026
OpenAI's flagship reasoning model with a 1M-token context window, built for hard coding, science and long-horizon agentic work.
The verdict
GPT-5.5 wins 4 of the 4 benchmarks these models share, against 0 for GPT-5. On price the gap is dramatic: GPT-5 works out roughly 3.3x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 400K for GPT-5.
Benchmark head-to-head 0–4
Specs & pricing
| GPT-5 | GPT-5.5 | |
|---|---|---|
| modhub Index | 70.7 | 77.2 |
| Input price / 1M | $1.25 | $5 |
| Output price / 1M | $10 | $30 |
| Context window | 400K | 1M |
| Max output | 128K | 128K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Sep 2024 | Jan 2026 |
| Released | Aug 2025 | Apr 2026 |
| Example monthly cost* | $27.50 | $95.00 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, GPT-5 or GPT-5.5?
- GPT-5.5 wins 4 of the 4 benchmarks these models share, against 0 for GPT-5. On price the gap is dramatic: GPT-5 works out roughly 3.3x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 400K for GPT-5.
- Which is cheaper, GPT-5 or GPT-5.5?
- GPT-5 costs $1.25/$10 per million input/output tokens, while GPT-5.5 costs $5/$30. For a typical workload of 10M input and 1.5M output tokens per month, that's $27.50 versus $95.00.
- Which model is better for coding, GPT-5 or GPT-5.5?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus 74.9% for GPT-5, making GPT-5.5 the stronger pick for coding agents.