Side-by-side comparison
GPT-5.1-Codex vs Gemini 2.5 Pro
OpenAI
GPT-5.1-Codex
👁 Vision
🔧 Tools
{} JSON
Input / 1M
$1.2500
Output / 1M
$10.0000
Google
Gemini 2.5 Pro
👁 Vision
🔧 Tools
{} JSON
Input / 1M
$1.2500
Output / 1M
$10.0000
| GPT-5.1-Codex | Gemini 2.5 Pro | |
|---|---|---|
| Provider | OpenAI | |
| Context window Maximum tokens (input + output) the model can process in a single request. Glossary → | 400,000 | 1,048,576 |
| Capabilities Optional capabilities the model advertises: vision (images), tools (function calling), json_mode (structured output). | vision, tools, json_mode | vision, tools, json_mode |
| Input $ / 1M tokens Cost for tokens you send (prompt + context). Cheaper side highlighted. Glossary → | 1.2500 | 1.2500 |
| Output $ / 1M tokens Cost for tokens the model generates. Output is normally 3–5× pricier than input. Glossary → | 10.0000 | 10.0000 |
Frequently asked questions
Which is cheaper, GPT-5.1-Codex or Gemini 2.5 Pro?
GPT-5.1-Codex is cheaper than Gemini 2.5 Pro on a 50/50 input/output blend by about $0 per 1M tokens. Exact savings depend on your input-vs-output ratio — use the cost calculator on this page for a workload-specific estimate.
Which has a larger context window, GPT-5.1-Codex or Gemini 2.5 Pro?
Gemini 2.5 Pro has the larger context window at 1M tokens versus 400k tokens for GPT-5.1-Codex. That means Gemini 2.5 Pro can ingest about 2.6x as much text per request.
What is the difference between GPT-5.1-Codex and Gemini 2.5 Pro?
GPT-5.1-Codex comes from OpenAI; Gemini 2.5 Pro comes from Google. They differ in pricing, context window, and supported capabilities — see the side-by-side table on this page for the exact figures, refreshed nightly.