Model comparison · Updated May 2026
Gemini 2.5 Pro vs GPT-5.5 Pro: Price, Context, Benchmarks (2026)
A direct, dated comparison of Gemini 2.5 Pro (Google) and GPT-5.5 Pro (OpenAI). Every number below is sourced from official provider docs and public benchmarks. If you need to make this decision today, the verdict is at the top.
30-second verdict
- Cheaper: Gemini 2.5 Pro (input $1.25 vs $30.00 per 1M tokens).
- Longer context: Gemini 2.5 Pro at 2M vs 1.1M.
- Stronger on SWE-bench Verified: GPT-5.5 Pro (~70% vs ~60%).
- Higher LMArena: GPT-5.5 Pro (1465 vs 1420).
Specs side-by-side
| Spec | Gemini 2.5 Pro | GPT-5.5 Pro |
|---|---|---|
| Vendor | OpenAI | |
| Input price (per 1M tokens) | $1.25 | $30.00 |
| Output price | $10.00 | $180.00 |
| Context window | 2M | 1.1M |
| Release date | 2025-06-17 | 2026-04-23 |
| SWE-bench Verified | ~60% | ~70% |
| HumanEval | ~92% | ~97% |
| LMArena (approx) | 1420 | 1465 |
| Open weights | No | No |
| Capabilities | reasoning, code, vision | reasoning, code, vision |
Pricing from official Google and OpenAI docs. Benchmark numbers from SWE-bench Verified, HumanEval, and LMArena public leaderboards as of May 2026.
Gemini 2.5 Pro — strengths and weaknesses
Strengths. Largest context window (2M), strong multimodal, generous AI Studio free tier.
Weaknesses. Recall drops past 500K, weaker on agentic edits than Claude / GPT.
Best for. Whole-repo Q&A, long PDFs, multimodal, free prototyping.
GPT-5.5 Pro — strengths and weaknesses
Strengths. Top-tier reasoning, asks better clarifying questions, deepest analysis.
Weaknesses. 6× the price of GPT-5.5 standard, slower.
Best for. High-stakes one-off problems, system design, math research.
Which one should you pick?
Pick Gemini 2.5 Pro if: whole-repo q&a, long pdfs, multimodal, free prototyping.
Pick GPT-5.5 Pro if: high-stakes one-off problems, system design, math research.
Use both if: you're building an agent or content pipeline. Route the high-stakes / hard-reasoning calls to whichever scores higher on the axis you care about, and the bulk / cheap calls to the other. Most production AI products run a 2-3 model router rather than betting on one.
Try them side-by-side
The Check.AI comparison tool lets you put both models in one table with all the numbers, switch capability filters, and share the resulting URL with your team.