Claude Opus 5.5vsGemini 2.5 Flash Preview 05-20 (thinking)

Claude Opus 5.5 is developed by Anthropic while Gemini 2.5 Flash Preview 05-20 (thinking) is developed by Google AI. Claude Opus 5.5 has a 1.0M token context window vs Gemini 2.5 Flash Preview 05-20 (thinking)'s 1.0M. You can compare their actual outputs across 1 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Opus 5.5 and Gemini 2.5 Flash Preview 05-20 (thinking) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 1 challenges so you can judge which fits your needs best.

Claude Opus 5.5 costs $4/M input tokens and Gemini 2.5 Flash Preview 05-20 (thinking) costs $0.15/M input tokens. Gemini 2.5 Flash Preview 05-20 (thinking) is $3.85/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of Claude Opus 5.5 and Gemini 2.5 Flash Preview 05-20 (thinking) 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.