Gemini 2.5 Pro vs GPT-5.5
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 · GPT-5.5 specs- PriceGemini 2.5 Pro
Gemini 2.5 Pro publishes pricing ($10.00 / 1M output tokens) while GPT-5.5 does not.
- Context windowGemini 2.5 Pro
Gemini 2.5 Pro accepts 2.1M tokens vs 400K, 5.2× the room for long documents and codebases.
- BenchmarksTie
No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores.
- ModalitiesGemini 2.5 Pro
Gemini 2.5 Pro supports 4 modalities (text, vision, audio, video) vs 3 for GPT-5.5.
- OpennessTie
Both are closed-weight, API-only.
On balance Gemini 2.5 Pro edges ahead, winning 3 of 5 categories against GPT-5.5's 0. Gemini 2.5 Pro publishes pricing ($10.00 / 1M output tokens) while GPT-5.5 does not. Gemini 2.5 Pro accepts 2.1M tokens vs 400K, 5.2× the room for long documents and codebases.
No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores. They differ in modality coverage, Gemini 2.5 Pro handles text, vision, audio, video while GPT-5.5 handles text, vision, audio, which can be the deciding factor before you even look at benchmarks. Both are closed-weight, API-only.
GPT-5.5 is the newer of the two, released 11 months after Gemini 2.5 Pro, which usually means a more recent knowledge cutoff and updated safety post-training. Gemini 2.5 Pro is usually picked for long context and rag workloads, while GPT-5.5 sees more deployments in agents and tool use. 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 | GPT-5.5 |
|---|---|---|
| Provider | OpenAI | |
| Released | Mar 2025 | Mar 2026 |
| Modalities | text, vision, audio, video | text, vision, audio |
| Context window | 2.1M tokens | 400K tokens |
| Max output | , | , |
| Input · 1M | $1.25 / 1M tokens | Pricing not published |
| Output · 1M | $10.00 / 1M tokens | Pricing not published |
| Knowledge cutoff | 2025-01 | , |
| 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 ,
- Heavy usage, 1M in / 500k out per day$188 vs ,
- RAG workload, 5M in / 200k out per day$248 vs ,
Light usage, 100k in / 50k out per day: pricing not directly comparable (one or both models are missing public per-token rates). Heavy usage, 1M in / 500k out per day: pricing not directly comparable (one or both models are missing public per-token rates). RAG workload, 5M in / 200k out per day: pricing not directly comparable (one or both models are missing public per-token rates).
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
- GPT-5.5Pricing unavailable
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
- GPQA84.0
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 400K for GPT-5.5.
- Multimodal needs covering video.
GPT-5.5 fits when…
- Industry-leading tool-use and function-calling reliability
- Strong end-to-end agent performance across SWE-bench and GAIA
- Wide ecosystem support, ChatGPT, Realtime API, Responses API
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 GPT-5.5 cheaper?
Per-token pricing isn't published for at least one of these models, check each model's spec page for current rates.Which has the larger context window?
Gemini 2.5 Pro accepts 2.1M tokens vs 400K for GPT-5.5.Is Gemini 2.5 Pro or GPT-5.5 better for coding?
Both Gemini 2.5 Pro and GPT-5.5 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 GPT-5.5 released?
Gemini 2.5 Pro was released by Google on 2025-03-25. GPT-5.5 was released by OpenAI on 2026-03-01.
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