What is the difference between Claude Opus 4 and Claude Opus 4.5?

Both are developed by Anthropic but target different use cases. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4 or Claude Opus 4.5?

It depends on your use case. Claude Opus 4 and Claude Opus 4.5 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How can I compare Claude Opus 4 and Claude Opus 4.5 on Rival?

This page shows a side-by-side comparison of Claude Opus 4 and Claude Opus 4.5 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Updated Nov 2025

Claude Opus 4vsClaude Opus 4.5

Claude Opus 4.5 is the newer model, released after Claude Opus 4.

Claude Opus 4 and Claude Opus 4.5 compared across 53 shared prompts
Spec	Claude Opus 4	Claude Opus 4.5
Input price	$15/M tokens	—
Output price	$75/M tokens	—
Context window	200K tokens	—
Weights	Closed	Closed
Free API (OpenRouter)	No	No
Released	May 2025	Nov 2025
SWE-bench Verified	72.5%	80.9%