ModelRefs / Gemini 2.5 Flash vs o3
Gemini 2.5 Flash vs o3
Gemini 2.5 Flash vs o3: side-by-side benchmarks, pricing, context windows, coding ability and deployment. Pick the right model for your stack.
Overview
Gemini 2.5 Flash: Gemini 2.5 Flash is Google DeepMind's price-performance model for low-latency, high-volume work that still needs reasoning, with thinking supported. It accepts text, image, audio and video input across a 1,048,576-token context window, returns up to 65,536 tokens, and carries a January 2025 knowledge cutoff. Google now limits access to existing users while keeping the model served.
o3: o3 is OpenAI's April 2025 reasoning model, applying deliberate chain-of-thought computation at inference time to mathematics, science and competitive programming tasks, and the release that brought OpenAI's scalable test-time compute approach to its production API. OpenAI has since deprecated it, scheduling the o3-2025-04-16 snapshot to shut down on 11 December 2026 with gpt-5.6-sol as the replacement.
Context window: Gemini 2.5 Flash accepts up to 1,000,000 tokens, o3 up to 200,000. Confirm the limit for your specific deployment channel before relying on it.
Gemini 2.5 Flash vs o3 at a glance
| Attribute | Gemini 2.5 Flash | o3 |
|---|---|---|
| Provider | OpenAI | |
| Released | 2025-06-17 | 2025-04-16 |
| Context window | 1,000,000 tokens | 200,000 tokens |
| Input price | $0.075/M tokens | $10/M tokens |
| Output price | $0.3/M tokens | $40/M tokens |
| Licence | Proprietary | Proprietary |
| Self-hostable | No, hosted only | No, hosted only |
| Modalities | text, vision, audio | text, vision |
Benchmarks reported for both
| Benchmark | Gemini 2.5 Flash | o3 | Reported |
|---|---|---|---|
| GPQA Diamond (accuracy) | 82.8 | 82.8 | Date not published |
Each row compares the same benchmark, the same reported metric, and the same task set. Scores are as published by their cited sources on the dates shown. Different runs still use different harnesses and prompts, so treat these as directional evidence rather than a head-to-head result.
Where they differ most
- Cost Efficiency: Gemini 2.5 Flash 95%, o3 13%. Gemini 2.5 Flash leads on this dimension.
- Reasoning: Gemini 2.5 Flash 86%, o3 86%. Both score the same on this dimension.
Capability scores are ModelRefs' own derived signals, not vendor claims or benchmark results. Validate against your own workload before relying on them.
Continue your research
Use these connected ModelRefs sections to compare alternatives, inspect implementation paths, and review the evidence and governance boundaries relevant to Gemini 2.5 Flash vs o3.
Frequently asked questions
Which is better, Gemini 2.5 Flash or o3?
Gemini 2.5 Flash and o3 target different workloads — see the benchmark and pricing tables for a side-by-side answer.
Is Gemini 2.5 Flash cheaper than o3?
Compare $0.00007 vs $0.0100 on this page.