GPT-5.5 vs OpenAI o4-mini
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
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.
OpenAI o4-mini
80.9OpenAI · Apr 2025
A compact reasoning model that punched far above its price on math — 92.7% on AIME 2025 at $1.10 per million input tokens.
The verdict
GPT-5.5 wins 3 of the 3 benchmarks these models share, against 0 for OpenAI o4-mini. On price the gap is dramatic: OpenAI o4-mini works out roughly 5.8x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 200K for OpenAI o4-mini.
Benchmark head-to-head 3–0
Specs & pricing
| GPT-5.5 | OpenAI o4-mini | |
|---|---|---|
| modhub Index | 77.2 | 80.9 |
| Input price / 1M | $5 | $1.1 |
| Output price / 1M | $30 | $4.4 |
| Context window | 1M | 200K |
| Max output | 128K | 100K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Jan 2026 | May 2024 |
| Released | Apr 2026 | Apr 2025 |
| Example monthly cost* | $95.00 | $17.60 |
* 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-5.5 or OpenAI o4-mini?
- GPT-5.5 wins 3 of the 3 benchmarks these models share, against 0 for OpenAI o4-mini. On price the gap is dramatic: OpenAI o4-mini works out roughly 5.8x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 200K for OpenAI o4-mini.
- Which is cheaper, GPT-5.5 or OpenAI o4-mini?
- GPT-5.5 costs $5/$30 per million input/output tokens, while OpenAI o4-mini costs $1.1/$4.4. For a typical workload of 10M input and 1.5M output tokens per month, that's $95.00 versus $17.60.
- Which model is better for coding, GPT-5.5 or OpenAI o4-mini?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus 68.1% for OpenAI o4-mini, making GPT-5.5 the stronger pick for coding agents.