Claude Opus 5 vs Gemini 3.1 Pro Preview
Facts only. This page does not pick a winner. For a picked winner, see the use case comparison on Tools.
| Claude Opus 5 | Gemini 3.1 Pro Preview | |
|---|---|---|
| API model IDs | claude-opus-5 | gemini-3.1-pro-preview |
| Context window | 1,000,000 | 1,048,576 |
| Lifecycle | active | active |
| License | proprietary | proprietary |
| Trains on API data | No | No |
| Zero data retention | on-request | on-request |
| Input per 1M tokens | $5 (verified 2026-09-08) | $2 (verified 2026-09-08) |
Frequently asked questions
- Which has the larger context window, Claude Opus 5 or Gemini 3.1 Pro Preview?
- Claude Opus 5 holds 1,000,000 tokens and Gemini 3.1 Pro Preview holds 1,048,576. Gemini 3.1 Pro Preview holds more. The context window counts the prompt, any attached files, and the reply together.
- Which is cheaper, Claude Opus 5 or Gemini 3.1 Pro Preview?
- Per million input tokens, Claude Opus 5 was $5 (verified 2026-09-08) and Gemini 3.1 Pro Preview was $2 (verified 2026-09-08). Gemini 3.1 Pro Preview is cheaper per input token. Output tokens cost $25 and $12 respectively, and output volume usually decides the bill.
- Does Claude Opus 5 or Gemini 3.1 Pro Preview train on API data?
- Claude Opus 5 does not train on API data by default, and Gemini 3.1 Pro Preview does not train on API data by default. Zero data retention is on-request for Claude Opus 5 and on-request for Gemini 3.1 Pro Preview. Verified 2026-09-08 and 2026-09-08 against the providers' own documentation.
- Is Claude Opus 5 or Gemini 3.1 Pro Preview being retired?
- Claude Opus 5 is active. Gemini 3.1 Pro Preview is active. Lifecycle checked 2026-09-08 and 2026-09-08. Pin a dated snapshot ID rather than an alias if a retirement would break you.