What is the difference between Claude Opus 5.5 and Gemini 2.5 Flash Preview (thinking)?

Claude Opus 5.5 is developed by Anthropic while Gemini 2.5 Flash Preview (thinking) is developed by Google AI. Claude Opus 5.5 has a 1.0M token context window vs Gemini 2.5 Flash Preview (thinking)'s 1.0M. You can compare their actual outputs across 2 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 5.5 or Gemini 2.5 Flash Preview (thinking)?

It depends on your use case. Claude Opus 5.5 and Gemini 2.5 Flash Preview (thinking) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 2 challenges so you can judge which fits your needs best.

How much does Claude Opus 5.5 cost compared to Gemini 2.5 Flash Preview (thinking)?

Claude Opus 5.5 costs $4/M input tokens and Gemini 2.5 Flash Preview (thinking) costs $0.175/M input tokens. Gemini 2.5 Flash Preview (thinking) is $3.83/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 Opus 5.5 and Gemini 2.5 Flash Preview (thinking) on Rival?

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

Updated Sep 2026

Claude Opus 5.5vsGemini 2.5 Flash Preview (thinking)

Gemini 2.5 Flash Preview (thinking) is cheaper than Claude Opus 5.5 at $0.175/M vs $4/M input tokens.

Claude Opus 5.5 and Gemini 2.5 Flash Preview (thinking) compared across 2 shared prompts
Spec	Claude Opus 5.5	Gemini 2.5 Flash Preview (thinking)
Input price	$4/M tokens	$0.175/M tokens
Output price	$20/M tokens	$3.5/M tokens
Context window	1.0M tokens	1.0M tokens
Weights	Closed	—
Free API (OpenRouter)	No	No
Released	Sep 2026	Apr 2025

Side by side

Same prompt, both answers

Opening lines from every prompt both answered. Formatting stripped, words untouched.

Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

Claude Opus 5.5300 words

Midnight Silk Noodles Creamy, tangy peanut noodles with a gentle kick, ready faster than takeout. Serves: 2 Prep time: 5 minutes Cook time: 10 minutes Total time: 15 minutes The 7 Ingredients 8 oz (225 g) spaghetti (or any long noodle) ¼ cup creamy peanut butter 3 tablespoons soy sauce 1 tablespoon honey (or sugar) 1…

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Gemini 2.5 Flash Preview (thinking)272 words

Okay, here is a simple, delicious savory recipe using only 7 common pantry ingredients. Dish Name: Sunshine Lentil Soup This is a bright, comforting soup that\'s surprisingly flavorful with just a few staples.

Read the full answer

Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

Claude Opus 5.5653 words

Your 1-Month Starter Plan for Better Health & Longevity The philosophy: Small, consistent changes beat dramatic overhauls. Each week builds on the last, so by Day 30 you'll have a foundation of habits instead of a burned-out resolution.

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Gemini 2.5 Flash Preview (thinking)867 words

Okay, here is a simple, actionable 1-month plan for a beginner focusing on Diet, Exercise, and Sleep for better health and longevity. Goal: To build foundational, sustainable habits in 3 key health areas over 30 days.

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Our Verdict

Claude Opus 5.5

Gemini 2.5 Flash Preview (thinking)Runner-up

Not enough votes to call it. On the specs, Claude Opus 5.5 has the edge: bigger model tier, newer.

Gemini 2.5 Flash Preview (thinking) costs 5.7x less per token.

Too close to call

API pricing

Cost per 1M tokens

Claude Opus 5.5

Input

$4.00

Output

$20.00

Gemini 2.5 Flash Preview (thinking)

Input

$0.17

23× cheaper

Output

$3.50

5.7× cheaper

Gemini 2.5 Flash Preview (thinking) is cheaper on both: 23× input, 5.7× output.

Where to run it

4 hosts

Claude Opus 5.54 hosts

HostInOutContextUptime

Amazon Bedrock$4.00 in$20.00 out1M99.8% up Azure AI Foundry$4.00 in$20.00 out1M100% up Anthropic$4.00 in$20.00 out1M100% up Google Vertex AI$4.00 in$20.00 out1M100% up

Gemini 2.5 Flash Preview (thinking)

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Same prompt, both answers

Simple 7-Ingredient Recipe

Beginner's Longevity Plan

Cost per 1M tokens

4 hosts

What we learned reading every model

Common questions

What is the difference between Claude Opus 5.5 and Gemini 2.5 Flash Preview (thinking)?

Which is better, Claude Opus 5.5 or Gemini 2.5 Flash Preview (thinking)?

How much does Claude Opus 5.5 cost compared to Gemini 2.5 Flash Preview (thinking)?

How can I compare Claude Opus 5.5 and Gemini 2.5 Flash Preview (thinking) on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages

Same prompt, both answers

Simple 7-Ingredient Recipe

Beginner's Longevity Plan

Cost per 1M tokens

4 hosts

What we learned reading every model

Common questions

What is the difference between Claude Opus 5.5 and Gemini 2.5 Flash Preview (thinking)?

Which is better, Claude Opus 5.5 or Gemini 2.5 Flash Preview (thinking)?

How much does Claude Opus 5.5 cost compared to Gemini 2.5 Flash Preview (thinking)?

How can I compare Claude Opus 5.5 and Gemini 2.5 Flash Preview (thinking) on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages