Claude Opus 4.5
A legacy Opus model with a November 2026 retirement date, still on the 200K context window and the explicit thinking parameter.
Last verified August 21, 2026 · 3 sources
The second-nearest retirement among active models: not sooner than 24 November 2026.
It costs the same as Opus 5 and does less
| Opus 4.5 | Opus 5 | |
|---|---|---|
| Price (in / out) | $5 / $25 | $5 / $25 — identical |
| Context window | 200K | 1M |
| Max output | 64K | 128K |
| Adaptive thinking | No | Yes |
| Extended thinking parameter | Yes | No |
| Reliable knowledge cutoff | May 2025 | May 2026 |
Same price, a fifth of the context, half the output ceiling, and a knowledge cutoff a year older. Unless you are pinned for reproducibility, there is no argument for staying — and there is a retirement date approaching.
The migration work, as with Sonnet 4.5, is the thinking parameter.
Specifications
| Property | Value |
|---|---|
| Claude API ID | claude-opus-4-5-20251101 |
| Claude API alias | claude-opus-4-5 |
| Amazon Bedrock ID | anthropic.claude-opus-4-5-20251101-v1:0 |
| Google Cloud ID | claude-opus-4-5@20251101 |
| Training data cutoff | August 2025 |
One thing to check before migrating
Opus 4.5 is in the group where regional and multi-region endpoint pricing first applied — a 10% premium over global endpoints on Bedrock and Google Cloud. If you are on a regional endpoint, that premium follows you to Opus 5.
Sources
- 01Models overview — Claude Platform DocsOfficialplatform.claude.com
- 02Introducing Claude Opus 4.5Officialanthropic.com
- 03Model deprecations — Claude Platform DocsOfficialplatform.claude.com
Page changelog
- VerifiedRetirement date confirmed as not sooner than 24 November 2026.