Models

Claude Opus 4.5

Anthropic · November 2025

An earlier Opus for chat, code and hard problems. Reads a fifth of what 4.6 and later hold.

Superseded by Claude Opus 4.6 →

  • Modalities

  • Context window

    200,000 tokens, ≈ 150,000 words · about 600 pages

  • Max output

    64,000 tokens, ≈ 48,000 words in a single answer

  • Knowledge cutoff

    May 2025

Reasoning effort

Default: High

  • Low

  • Medium

  • High

Providers

Files you can attach

  • ImagesJPG, PNG, GIF, WEBP
  • DocumentsPDF
  • Text and codeTXT, MD, CSV, TSV, RPT, LOG, PY, TS, TSX, JS, JSX, CS, GO, JAVA, KT, SWIFT, CPP, C, H, PHP, RB, SQL, SH, PS1, HTML, CSS, SCSS, JSON, YAML, YML, XML, INI

Tools

  • Web searchSupported
  • Code interpreterSupported

Features

  • StreamingSupported
  • Function callingSupported
  • Structured outputsSupported
  • Fine-tuningNot supported

Ready to try it?

Log in

Bring your own API key · Your chats stay in your browser