What is the difference between Claude Sonnet 4.5 and OpenAI o3?

Claude Sonnet 4.5 is developed by Anthropic while OpenAI o3 is developed by OpenAI. You can compare their actual outputs across 43 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or OpenAI o3?

It depends on your use case. Claude Sonnet 4.5 and OpenAI o3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 43 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4.5 cost compared to OpenAI o3?

Claude Sonnet 4.5 costs $3/M input tokens and OpenAI o3 costs $10/M input tokens. Claude Sonnet 4.5 is $7.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Claude Sonnet 4.5 and OpenAI o3 on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and OpenAI o3 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 Sep 2025

Claude Sonnet 4.5vsOpenAI o3

Claude Sonnet 4.5 is cheaper than OpenAI o3 at $3/M vs $10/M input tokens.

Claude Sonnet 4.5 and OpenAI o3 compared across 43 shared prompts
Spec	Claude Sonnet 4.5	OpenAI o3
Input price	$3/M tokens	$10/M tokens
Output price	$15/M tokens	$40/M tokens
Context window	200K tokens	—
Weights	Closed	Closed
Free API (OpenRouter)	No	No
Released	Sep 2025	Apr 2025
SWE-bench Verified	77.2%	69.1%