Gemini 2.5 Flash vs GPT-5.5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Gemini 2.5 Flash
Google · Jun 2025
The 2025 fast-tier favorite: hybrid reasoning, full multimodality and a 1M context at $0.30/$2.50.
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 Gemini 2.5 Flash. On price the gap is dramatic: Gemini 2.5 Flash works out roughly 13x cheaper per blended million tokens. Gemini 2.5 Flash also takes 1.0M of context versus 1M for GPT-5.5.
Benchmark head-to-head 0–2
Specs & pricing
| Gemini 2.5 Flash | GPT-5.5 | |
|---|---|---|
| modhub Index | — | 77.2 |
| Input price / 1M | $0.3 | $5 |
| Output price / 1M | $2.5 | $30 |
| Context window | 1.0M | 1M |
| Max output | 66K | 128K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image, audio, video | text, image |
| Knowledge cutoff | Jan 2025 | Jan 2026 |
| Released | Jun 2025 | Apr 2026 |
| Example monthly cost* | $6.75 | $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 2.5 Flash or GPT-5.5?
- GPT-5.5 wins 2 of the 2 benchmarks these models share, against 0 for Gemini 2.5 Flash. On price the gap is dramatic: Gemini 2.5 Flash works out roughly 13x cheaper per blended million tokens. Gemini 2.5 Flash also takes 1.0M of context versus 1M for GPT-5.5.
- Which is cheaper, Gemini 2.5 Flash or GPT-5.5?
- Gemini 2.5 Flash costs $0.3/$2.5 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 $6.75 versus $95.00.
- Which model is better for coding, Gemini 2.5 Flash or GPT-5.5?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus ~48.9% for Gemini 2.5 Flash, making GPT-5.5 the stronger pick for coding agents.