Gemini 2.5 Flash vs OpenAI o3
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.
OpenAI o3
68.9OpenAI · Apr 2025
OpenAI's dedicated 2025 reasoning model that pioneered thinking-with-images and agentic tool use within chain-of-thought.
The verdict
OpenAI o3 wins 3 of the 3 benchmarks these models share, against 0 for Gemini 2.5 Flash. On price the gap is dramatic: Gemini 2.5 Flash works out roughly 4.1x cheaper per blended million tokens. Gemini 2.5 Flash also takes 1.0M of context versus 200K for OpenAI o3.
Benchmark head-to-head 0–3
Specs & pricing
| Gemini 2.5 Flash | OpenAI o3 | |
|---|---|---|
| modhub Index | — | 68.9 |
| Input price / 1M | $0.3 | $2 |
| Output price / 1M | $2.5 | $8 |
| Context window | 1.0M | 200K |
| Max output | 66K | 100K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image, audio, video | text, image |
| Knowledge cutoff | Jan 2025 | May 2024 |
| Released | Jun 2025 | Apr 2025 |
| Example monthly cost* | $6.75 | $32.00 |
* 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 OpenAI o3?
- OpenAI o3 wins 3 of the 3 benchmarks these models share, against 0 for Gemini 2.5 Flash. On price the gap is dramatic: Gemini 2.5 Flash works out roughly 4.1x cheaper per blended million tokens. Gemini 2.5 Flash also takes 1.0M of context versus 200K for OpenAI o3.
- Which is cheaper, Gemini 2.5 Flash or OpenAI o3?
- Gemini 2.5 Flash costs $0.3/$2.5 per million input/output tokens, while OpenAI o3 costs $2/$8. For a typical workload of 10M input and 1.5M output tokens per month, that's $6.75 versus $32.00.
- Which model is better for coding, Gemini 2.5 Flash or OpenAI o3?
- On SWE-bench Verified — the standard agentic-coding benchmark — OpenAI o3 scores 69.1% versus ~48.9% for Gemini 2.5 Flash, making OpenAI o3 the stronger pick for coding agents.