Gemini 3.5 Flash vs GPT-5.5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Gemini 3.5 Flash
Google · May 2026
Google's I/O 2026 headliner: near-Pro intelligence at Flash speed, 78.8% on SWE-bench Verified with full multimodal input.
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 1 of the 1 benchmarks these models share, against 0 for Gemini 3.5 Flash. On price the gap is dramatic: Gemini 3.5 Flash works out roughly 3.3x cheaper per blended million tokens.
Benchmark head-to-head 0–1
Specs & pricing
| Gemini 3.5 Flash | GPT-5.5 | |
|---|---|---|
| modhub Index | — | 77.2 |
| Input price / 1M | $1.5 | $5 |
| Output price / 1M | $9 | $30 |
| Context window | 1M | 1M |
| Max output | 66K | 128K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image, audio, video | text, image |
| Knowledge cutoff | Feb 2026 | Jan 2026 |
| Released | May 2026 | Apr 2026 |
| Example monthly cost* | $28.50 | $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, Gemini 3.5 Flash or GPT-5.5?
- GPT-5.5 wins 1 of the 1 benchmarks these models share, against 0 for Gemini 3.5 Flash. On price the gap is dramatic: Gemini 3.5 Flash works out roughly 3.3x cheaper per blended million tokens.
- Which is cheaper, Gemini 3.5 Flash or GPT-5.5?
- Gemini 3.5 Flash costs $1.5/$9 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 $28.50 versus $95.00.
- Which model is better for coding, Gemini 3.5 Flash or GPT-5.5?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus 78.8% for Gemini 3.5 Flash, making GPT-5.5 the stronger pick for coding agents.