GPT-4o vs GPT-5.5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
GPT-4o
OpenAI · May 2024
The 2024 omni-modal classic with native audio in and out; superseded at the frontier but still everywhere in production.
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 2 of the 2 benchmarks these models share, against 0 for GPT-4o. GPT-4o is about 2.6x cheaper per blended million tokens (3:1 input:output mix). GPT-5.5 also takes 1M of context versus 128K for GPT-4o.
Benchmark head-to-head 0–2
Specs & pricing
| GPT-4o | GPT-5.5 | |
|---|---|---|
| modhub Index | — | 77.2 |
| Input price / 1M | $2.5 | $5 |
| Output price / 1M | $10 | $30 |
| Context window | 128K | 1M |
| Max output | 16K | 128K |
| Open weights | no | no |
| Reasoning model | no | yes |
| Multimodal input | text, image, audio | text, image |
| Knowledge cutoff | Oct 2023 | Jan 2026 |
| Released | May 2024 | Apr 2026 |
| Example monthly cost* | $40.00 | $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-4o or GPT-5.5?
- GPT-5.5 wins 2 of the 2 benchmarks these models share, against 0 for GPT-4o. GPT-4o is about 2.6x cheaper per blended million tokens (3:1 input:output mix). GPT-5.5 also takes 1M of context versus 128K for GPT-4o.
- Which is cheaper, GPT-4o or GPT-5.5?
- GPT-4o costs $2.5/$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 $40.00 versus $95.00.
- Which model is better for coding, GPT-4o or GPT-5.5?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus 33.2% for GPT-4o, making GPT-5.5 the stronger pick for coding agents.