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  5. Claude Opus 5.5vsGemini 2.5 Flash Preview
Updated Sep 2026

Claude Opus 5.5vsGemini 2.5 Flash Preview

Gemini 2.5 Flash Preview is cheaper than Claude Opus 5.5 at $0.15/M vs $4/M input tokens.

Claude Opus 5.5 and Gemini 2.5 Flash Preview compared across 2 shared prompts
SpecClaude Opus 5.5Gemini 2.5 Flash Preview
Input price$4/M tokens$0.15/M tokens
Output price$20/M tokens$0.6/M tokens
Context window1.0M tokens1.0M tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedSep 2026Apr 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 Preview221 words
Dish Name: Sunshine Lemon-Ricotta Mugs (Sweet & Simple!) This light and flavorful dessert comes together quickly for a little sweet treat . Ingredients (7 Common Pantry Staples): Ricotta cheese (whole milk or part-skim) Granulated sugar Lemon zest (from one lemon) Vanilla extract All-purpose flour Baking powder Large…
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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.
Read the full answer
Gemini 2.5 Flash Preview960 words
<s) with practical, beginner-friendly tips for each.\"\nHere\'s a simple, actionable 1-month plan for someone starting their journey towards better health and longev\nity, focusing on three key areas: Diet, Movement, and Sleep.\n\nThis plan is designed to be beginner-friendly and build sustainable habits.
Read the full answer
Our Verdict
Claude Opus 5.5
Claude Opus 5.5
Gemini 2.5 Flash Preview
Gemini 2.5 Flash PreviewRunner-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 costs 33x 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
Input
$0.15
27× cheaper
Output
$0.60
33× cheaper

Gemini 2.5 Flash Preview is cheaper on both: 27× input, 33× output.

Where to run it

4 hosts

Claude Opus 5.54 hosts
HostInOutContextUptime
Amazon Bedrock$4.00 in·$20.00 out·1M·99.8% upAzure AI Foundry$4.00 in·$20.00 out·1M·100% upAnthropic$4.00 in·$20.00 out·1M·100% upGoogle Vertex AI$4.00 in·$20.00 out·1M·100% up
Gemini 2.5 Flash Preview

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

Claude Opus 5.5 is developed by Anthropic while Gemini 2.5 Flash Preview is developed by Google AI. Claude Opus 5.5 has a 1.0M token context window vs Gemini 2.5 Flash Preview's 1.0M. You can compare their actual outputs across 2 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 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.

Claude Opus 5.5 costs $4/M input tokens and Gemini 2.5 Flash Preview costs $0.15/M input tokens. Gemini 2.5 Flash Preview 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 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.

Keep exploring

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Model pages

Claude Opus 5.5 logo
Claude Opus 5.519 outputs, specs and price
Gemini 2.5 Flash Preview logo
Gemini 2.5 Flash Preview28 outputs, specs and price
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