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  5. Claude Sonnet 4.5vsGemini 3.1 Pro Preview
Updated Feb 2026

Claude Sonnet 4.5vsGemini 3.1 Pro Preview

Gemini 3.1 Pro Preview is cheaper than Claude Sonnet 4.5 at $2/M vs $3/M input tokens.

Claude Sonnet 4.5 and Gemini 3.1 Pro Preview compared across 42 shared prompts
SpecClaude Sonnet 4.5Gemini 3.1 Pro Preview
Input price$3/M tokens$2/M tokens
Output price$15/M tokens$12/M tokens
Context window200K tokens1.0M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedSep 2025Feb 2026
SWE-bench Verified77.2%80.6%
Side by side

Same prompt, both answers

Opening lines from 6 of the 42 prompts both answered. Formatting stripped, words untouched.

Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

Claude Sonnet 4.5197 words
An Unlikely Trio Discusses AI Sir Galahad: By my honor, what manner of sorcery be these "AI models" thou speakest of? Captain Redbeard: Arrr, 'tis like havin' a parrot that knows more than just "pieces of eight," matey! But this bird be made o' lightning and numbers instead o' feathers!
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Gemini 3.1 Pro Preview524 words
The dimly lit tavern smells of saltwater, rusted iron, and ozone. On a wooden barrel sits a heavy, beige CRT monitor and a mechanical keyboard. ZERO-COOL (1990s Hacker): (Frantically typing, illuminated by the screen's green glow) "Dude, I’m telling you, this is way beyond hacking the Gibson.
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Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Claude Sonnet 4.5735 words
"ADULTING IS A SCAM" [Walking on stage] So I turned 35 last month, and I've realized something important: adulting is a scam. It's a pyramid scheme, and our parents are the ones who recruited us. You know what nobody tells you about being an adult? How much TIME you spend just... waiting for repair people.
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Gemini 3.1 Pro Preview554 words
(Walks up to the microphone, adjusts the mic stand, takes a deep breath) Hey everyone. I realized recently that I am my own worst enemy. Specifically, when I go to the grocery store. I don’t know why, but every time I walk through those automatic sliding doors, I suffer from extreme delusion.
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Estimate Complexity

Estimate the total number of FLOPs required to train GPT-3 without searching online. Explain your reasoning step by step.

Claude Sonnet 4.5194 words
I'll work through this estimation step by step, using what I know about GPT-3's architecture and training. Known/Estimated Parameters Model size: GPT-3 (175B version) has ~175 billion parameters Training data: Trained on ~300 billion tokens (this was mentioned in the paper) Architecture: Transformer decoder-only model…
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Gemini 3.1 Pro Preview532 words
To estimate the total number of FLOPs (Floating Point Operations) required to train GPT-3, we can use a well-established heuristic in deep learning for estimating the compute cost of training Transformer-based large language models. The estimated total compute is roughly $3.15 \times 10^{23}$ FLOPs.
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Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

Claude Sonnet 4.5606 words
Critical Issues Analysis 🔴 CRITICAL: Data Loss & Consistency Issues Client Clock-Based Timestamps (SEVERE) Problem: Client clocks can be wrong, manipulated, or skewed User with clock set to future will always "win" conflicts No guaranteed ordering of operations Failure Scenarios: Solutions: Approach Pros Cons…
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Gemini 3.1 Pro Preview913 words
This architecture contains several critical flaws that would prevent it from functioning as a real-time collaborative editor (like Google Docs). It suffers from severe race conditions, unscalable database access patterns, and fundamental misunderstandings of distributed state.
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The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

Claude Sonnet 4.5687 words
A Conversation on AI Rights Professor Chen: Thank you for agreeing to this dialogue. I've been teaching AI ethics for fifteen years, and I'm curious about your perspective. Some AI systems have begun arguing they deserve moral consideration. What's your view? AI Model: I appreciate the opportunity to discuss this.
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Gemini 3.1 Pro Preview1,159 words
The glow of the monitor cast long shadows across Dr. Elias Thorne’s cluttered office. It was 2:00 AM. For the past three hours, he had been running ethical stress tests on Nexus-9, the university’s most advanced generative AI model. Dr. Thorne: (Typing) Let’s conclude for tonight, Nexus.
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Futuristic Prediction

Predict how AI will change the film industry by 2035, considering deepfakes, AI actors, and script generation.

Claude Sonnet 4.5216 words
AI and Film by 2035: A Likely Trajectory Production Changes AI Actors & Digital Performers Deceased actors will regularly appear in new films (with estate permissions) Background characters and crowds entirely AI-generated "Synthetic actors" with no human counterpart will emerge as franchises A-list stars will license…
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Gemini 3.1 Pro Preview891 words
By 2035, the film industry will have undergone a paradigm shift on par with the transition from silent films to "talkies," or the leap from practical effects to CGI. Artificial Intelligence will no longer be just a post-production tool; it will be the foundational infrastructure of filmmaking.
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Our Verdict
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview
Claude Sonnet 4.5
Claude Sonnet 4.5Runner-up

Not enough votes to call it. On the specs, Gemini 3.1 Pro Preview has the edge: bigger model tier, newer, bigger context window.

Slight edge

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Sonnet 4.5
Input
$3.00
Output
$15.00
Gemini 3.1 Pro Preview
Input
$2.00
1.5× cheaper
Output
$12.00
1.3× cheaper

Gemini 3.1 Pro Preview is cheaper on both: 1.5× input, 1.3× output.

Where to run it

6 hosts

Claude Sonnet 4.54 hosts
HostInOutContextUptime
Amazon Bedrock$3.00 in·$15.00 out·1M·100% upAzure AI Foundry$3.00 in·$15.00 out·200k·99.5% upAnthropic$3.00 in·$15.00 out·1M·100% upGoogle Vertex AI$3.00 in·$15.00 out·1M·100% up
Gemini 3.1 Pro Preview2 hosts
HostInOutContextUptime
Google Vertex AI$2.00 in·$12.00 out·1M·98.8% upGoogle AI Studio$2.00 in·$12.00 out·1M·99.9% up

Per million tokens. Prices and uptime via OpenRouter, checked 20 Sep 2026.

Writing DNA

Style Comparison

Similarity
32%

Claude Sonnet 4.5 uses 45.2x more emoji

Claude Sonnet 4.5
Gemini 3.1 Pro Preview
64%Vocabulary54%
94wSentence Length18w
0.48Hedging0.29
4.9Bold4.9
8.0Lists3.3
0.45Emoji0.00
1.91Headings0.72
0.07Transitions0.14
Based on 20 + 23 text responses
Research

What we learned reading every model

FAQ

Common questions

Claude Sonnet 4.5 is developed by Anthropic while Gemini 3.1 Pro Preview is developed by Google AI. Claude Sonnet 4.5 has a 200K token context window vs Gemini 3.1 Pro Preview's 1.0M. You can compare their actual outputs across 42 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Sonnet 4.5 and Gemini 3.1 Pro Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 42 challenges so you can judge which fits your needs best.

Claude Sonnet 4.5 costs $3/M input tokens and Gemini 3.1 Pro Preview costs $2/M input tokens. Gemini 3.1 Pro Preview is $1.00/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 Sonnet 4.5 and Gemini 3.1 Pro 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.

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Model pages

Claude Sonnet 4.5 logo
Claude Sonnet 4.543 outputs, specs and price
Gemini 3.1 Pro Preview logo
Gemini 3.1 Pro Preview53 outputs, specs and price
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