Gemini 3.5 Pro vs GPT-5.5

Gemini 3.5 Pro versus GPT-5.5 is the canonical Google-versus-OpenAI frontier comparison for the Gemini 3.5 Pro GA window. Gemini brings a sourced 2M-token context window and preview status. GPT-5.5 is already available with tracked pricing, provider routes, and benchmark coverage for coding, reasoning, and terminal-agent work.

Pick GPT-5.5 for production decisions today because it has public pricing, multiple provider routes, and benchmark rows in the local data. Keep Gemini 3.5 Pro on the shortlist when the workload is bottlenecked by context length or Google ecosystem routing, but wait for GA pricing, public provider routes, and independent benchmark evidence before replacing GPT-5.5.

Decision scorecard

Local evidence first

Signal	Gemini 3.5 Pro	GPT-5.5	How to read it
Best for	reasoning-heavy apps, multimodal apps, and long-context analysis	reasoning-heavy apps, multimodal apps, and tool-calling agents	Use-case synthesis from product type, capability flags, context, and provider data.
Decision fit	Long context and Vision	Coding, RAG, and Agents	Primary workload tags from local decision data.
Context window	2m	1.05m	Higher is better when prompts, retrieval chunks, or transcripts are large.
Cheapest output	-	$30/1M tokens	Cheapest tracked provider route; verify your exact region and tier.
Provider routes	0 tracked	4 tracked	Broader coverage can reduce vendor lock-in and fallback risk.
Shared benchmarks	0 shared	0 shared	No shared benchmark scores are available for this pair yet.

Decision tradeoffs

Choose Gemini 3.5 Pro when...

Gemini 3.5 Pro has the larger context window for long prompts, retrieval packs, or transcript analysis.
Local decision data tags Gemini 3.5 Pro for Long context and Vision.

Choose GPT-5.5 when...

GPT-5.5 has broader tracked provider coverage for fallback and procurement flexibility.
GPT-5.5 uniquely exposes Function calling, Tool use, and Structured outputs in local model data.
Local decision data tags GPT-5.5 for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Requests / monthInput tokens / requestOutput tokens / request

Gemini 3.5 Pro

Unavailable

No complete token price in local provider data

GPT-5.5

$11,500

Cheapest tracked route/tier: OpenAI API 0-272K input tokens

Cost delta unavailable until both models have sourced input and output token prices.

Switch friction

Gemini 3.5 Pro -> GPT-5.5

No overlapping tracked provider route is sourced for Gemini 3.5 Pro and GPT-5.5; plan for SDK, billing, or endpoint changes.
GPT-5.5 adds Function calling, Tool use, and Structured outputs in local capability data.

GPT-5.5 -> Gemini 3.5 Pro

No overlapping tracked provider route is sourced for GPT-5.5 and Gemini 3.5 Pro; plan for SDK, billing, or endpoint changes.
Check replacement coverage for Function calling, Tool use, and Structured outputs before moving production traffic.

Specs

Specification	Gemini 3.5 Pro Google DeepMind	GPT-5.5 OpenAI
Released	2026-05-19	2026-04-23
Context window	2m	1.05m
Parameters	—	—
Architecture	-	Decoder Only
License	Proprietary	Proprietary
Openness	Proprietary	Proprietary
Commercial use	Commercial use: conditional	Commercial use: conditional
Knowledge cutoff	-	2025-12

Pricing and availability

Pricing attribute	Gemini 3.5 Pro	GPT-5.5
Input price	-	0-272K input tokens $5/1M tokens Standard GPT-5.5 token pricing before the long-context surcharge threshold. 272K+ input tokens $8/1M tokens Long-context surcharge applies above 272K input tokens for the full session.
Output price	-	0-272K input tokens $30/1M tokens Standard GPT-5.5 token pricing before the long-context surcharge threshold. 272K+ input tokens $36/1M tokens Long-context surcharge applies above 272K input tokens for the full session.
Providers	-	OpenAI API OpenRouter Vercel AI Gateway AWS Bedrock

Capabilities

Capability	Gemini 3.5 Pro	GPT-5.5
Vision	Yes	Yes
Multimodal	Yes	Yes
Reasoning	Yes	Yes
Function calling	No	Yes
Tool use	No	Yes
Structured outputs	No	Yes
Code execution	No	Yes
IDE integration	No	No
Computer use	No	No
Parallel agents	No	No

Benchmarks

No shared benchmark scores are currently available for this pair.

Deep dive

Gemini's sourced differentiator is context. The seed tracks Gemini 3.5 Pro at 2M tokens, nearly twice GPT-5.5's 1.05M-token window. That can matter for full-codebase review, long legal or technical packs, and multimodal prompt bundles.

GPT-5.5 has the stronger current production evidence. It has tracked token pricing, provider routes, GPQA, SWE-bench, Terminal-Bench, MMLU, HumanEval, and related benchmark rows. Gemini 3.5 Pro has no comparable public benchmark set yet.

The cost comparison is not ready. GPT-5.5 has sourced token pricing, including its long-context tiering. Gemini 3.5 Pro pricing is intentionally blank until Google confirms official GA rates, so avoid speculative spend estimates.

The practical workflow is to keep GPT-5.5 as the default production option and run Gemini 3.5 Pro evaluations only when Google exposes the exact endpoint, pricing, and context behavior your app will use.

FAQ

Which has a larger context window, Gemini 3.5 Pro or GPT-5.5?

Gemini 3.5 Pro supports 2m tokens, while GPT-5.5 supports 1.05m tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.

Is Gemini 3.5 Pro or GPT-5.5 open source?

Gemini 3.5 Pro is listed under Proprietary. GPT-5.5 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.

Which is better for vision, Gemini 3.5 Pro or GPT-5.5?

Both Gemini 3.5 Pro and GPT-5.5 expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.

Which is better for multimodal input, Gemini 3.5 Pro or GPT-5.5?

Both Gemini 3.5 Pro and GPT-5.5 expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.

Which is better for reasoning mode, Gemini 3.5 Pro or GPT-5.5?

Both Gemini 3.5 Pro and GPT-5.5 expose reasoning mode. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.

Where can I run Gemini 3.5 Pro and GPT-5.5?

Gemini 3.5 Pro is available on the tracked providers still being sourced. GPT-5.5 is available on OpenAI API, OpenRouter, Vercel AI Gateway, and AWS Bedrock. Provider coverage can affect latency, region availability, compliance posture, and fallback options.

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Model pages

Labs and families

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Last reviewed: 2026-06-20. Data sourced from public model cards and provider documentation.

Both models

Gemini 3.5 Pro GPT-5.5