Gemini 2.5 Pro vs o3
A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.
Updated
Gemini 2.5 Pro specs · o3 specs- Priceo3
o3 is roughly 1.3× cheaper on output tokens ($8.00 vs $10.00 per 1M).
- Context windowGemini 2.5 Pro
Gemini 2.5 Pro accepts 2.1M tokens vs 200K, 10.5× the room for long documents and codebases.
- Benchmarkso3
o3 leads in 1 of 1 shared benchmarks; the biggest gap is on GPQA (graduate-level reasoning), where it scores 87.7 vs 84.0.
- ModalitiesGemini 2.5 Pro
Gemini 2.5 Pro supports 4 modalities (text, vision, audio, video) vs 2 for o3.
- OpennessTie
Both are closed-weight, API-only.
It's a genuine coin-flip between Gemini 2.5 Pro and o3: 2 category wins each, with the rest tied. o3 is roughly 1.3× cheaper on output tokens ($8.00 vs $10.00 per 1M). Gemini 2.5 Pro accepts 2.1M tokens vs 200K, 10.5× the room for long documents and codebases.
o3 leads in 1 of 1 shared benchmarks; the biggest gap is on GPQA (graduate-level reasoning), where it scores 87.7 vs 84.0. They differ in modality coverage, Gemini 2.5 Pro handles text, vision, audio, video while o3 handles text, vision, which can be the deciding factor before you even look at benchmarks. Both are closed-weight, API-only.
Both shipped within roughly a month of each other in 2025, so they share the same generation of training data and tooling. Gemini 2.5 Pro is usually picked for long context and rag workloads, while o3 sees more deployments in reasoning and math. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.
Side-by-side specs
| Spec | Gemini 2.5 Pro | o3 |
|---|---|---|
| Provider | OpenAI | |
| Released | Mar 2025 | Apr 2025 |
| Modalities | text, vision, audio, video | text, vision |
| Context window | 2.1M tokens | 200K tokens |
| Max output | , | , |
| Input · 1M | $1.25 / 1M tokens | $2.00 / 1M tokens |
| Output · 1M | $10.00 / 1M tokens | $8.00 / 1M tokens |
| Knowledge cutoff | 2025-01 | 2024-06 |
| Open weights | No | No |
| API available | Yes | Yes |
Pricing at scale
What you'd actually pay at typical workloads. Numbers come from each model's published per-million-token rates.
- Light usage, 100k in / 50k out per day$18.75 vs $18.00
- Heavy usage, 1M in / 500k out per day$188 vs $180
- RAG workload, 5M in / 200k out per day$248 vs $348
Light usage, 100k in / 50k out per day: $18.75 vs $18.00 per month, model B comes out ahead. Heavy usage, 1M in / 500k out per day: $188 vs $180 per month, model B comes out ahead. RAG workload, 5M in / 200k out per day: $248 vs $348 per month, model A comes out ahead.
Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.
- Gemini 2.5 Pro$0.625
- o3$0.600
Benchmarks compared
Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.
- MMLU86.0
- HumanEval,95.0
- GPQA84.087.7
Gemini 2.5 Pro fits when…
- 2M-token context window
- Strong on long-document tasks
- Native multimodal handling
- Long-context tasks, handles 2.1M tokens vs 200K for o3.
- Multimodal needs covering audio, video.
o3 fits when…
- Industry-leading reasoning depth at launch
- Strong on math, science, and abstract puzzles
- Tool-use during reasoning loops
- Cost-sensitive workloads, 1.3× cheaper than Gemini 2.5 Pro on output tokens.
Consider Gemini 3 Pro
Google's late-2025 flagship, set new benchmarks on long-context, vision, and reasoning at competitive pricing.
Frequently asked
Is Gemini 2.5 Pro or o3 cheaper?
o3 is cheaper at $8.00 / 1M tokens per million output tokens, vs $10.00 / 1M tokens for Gemini 2.5 Pro.Which has the larger context window?
Gemini 2.5 Pro accepts 2.1M tokens vs 200K for o3.Is Gemini 2.5 Pro or o3 better for coding?
Both Gemini 2.5 Pro and o3 are competitive on coding benchmarks. See each model's individual spec page for HumanEval and SWE-bench scores where published. For an opinionated pick, consult our Best LLM for Coding ranking.Are either of these models open source?
Neither model ships open weights, both are accessible only via their respective providers' APIs.When were Gemini 2.5 Pro and o3 released?
Gemini 2.5 Pro was released by Google on 2025-03-25. o3 was released by OpenAI on 2025-04-16.
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