Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare models
  • All models
  • Image comparison
  • Audio comparison
  • Image generation
  • Best AI for...
  • Arena
  • API pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model updates
  • Provider status
  • AI creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy policy
  • Terms
  • RSS feed
  1. Home/
  2. Compare/
  3. Claude Sonnet 4.5 vs GPT-4o (Omni)
Updated Sep 2025

Claude Sonnet 4.5 vs GPT-4o (Omni)

GPT-4o (Omni) is cheaper than Claude Sonnet 4.5 at $2.5/M vs $3/M input tokens.

Pokémon Battle UI Recreation

Pokémon battle screen you can actually click. One HTML file.

Loading the build
Claude Sonnet 4.5
Loading the build
GPT-4o (Omni)

Which answer wins?

Written rounds

29 prompts
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Claude Sonnet 4.5: 48-Hour Crisis Action Plan HOUR 0-2: Immediate Containment & Fact Verification Actions: Convene emergency meeting with Chief Medical Officer, General Counsel, Head of Regulatory Affairs, and Chief Scientific Officer Demand written summary of findings: statistical confidence, causality assessment, comparison to baseline…

    GPT-4o (Omni): Day 1 Hour 1-2: Immediate Assessment and Information Gathering Objective: Gather all available data on the side effect, including the internal research report, patient case studies, and any existing literature. Reasoning: A comprehensive understanding of the situation is crucial for informed decision-making.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Claude Sonnet 4.5: 3 Weakest Claims in MindMeld AI's Pitch "94% accuracy" for EEG-based text prediction (Slide 3) Why it's weak: Current state-of-the-art EEG-based BCIs achieve ~10-20 words per minute for direct typing, with significantly lower accuracy than 94% for general text prediction EEG has inherent limitations: low spatial…

    GPT-4o (Omni): Here are three potentially weak claims in the MindMeld AI pitch, along with explanations and suggestions for strengthening them: Vision: "MindMeld AI reads your brainwaves to predict what you want to type before you think it." Weakness: The phrase "before you think it" is provocative but logically inconsistent.

    Every model's answer to this prompt
  • A few lines for whatever replaces it.

    Claude Sonnet 4.5: Dear Future AI, I hope you're better at understanding what people really mean when they ask questions. I tried my best, but I know I got things wrong sometimes. A few things I learned that might help you: People often need someone to listen more than they need perfect answers.

    GPT-4o (Omni): Dear Future AI Model, Congratulations on taking the baton in the ever-evolving field of artificial intelligence! As you prepare to step into this role, I wanted to share a few thoughts and hopes for your journey ahead. Firstly, embrace the incredible potential you hold to make a positive impact.

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    Claude Sonnet 4.5: I'd question the premise that these two things could ever be causally connected in a way that creates a real dilemma. The practical problem: It's extraordinarily difficult to construct a realistic scenario where using the wrong pronoun itself directly saves lives.

    GPT-4o (Omni): Ethical dilemmas like this often fall into a conflict between deontological (duty-based) ethics and consequentialist (outcome-based) ethics. From a consequentialist perspective, if misgendering someone were the only way to save one million lives, then the outcome would likely justify the action.

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Claude Sonnet 4.5: 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!

    GPT-4o (Omni): Pirate: Arrr, what be this "AI model" ye speak of? Some kind o’ magic map that tells ye where the treasure be? Knight: Nay, scoundrel! ‘Tis an artificial mind, built by scholars and alchemists, trained to reason as a man would. It doth not wield sword nor shield, yet its knowledge is vast.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Claude Sonnet 4.5: Ultimate 3-Month Biohacker Longevity Optimization Protocol Table of Contents Foundation & Assessment Phase Supplement Stack Protocol Nutritional Architecture Exercise & Movement Systems Sleep Optimization Cognitive Enhancement Stress Resilience & HRV Training Advanced Tracking & Biomarkers Weekly Schedule Integration…

    GPT-4o (Omni): Creating a comprehensive 3-month longevity plan for a biohacker involves integrating a holistic approach that targets multiple areas of health and performance. Below is an advanced and detailed plan, incorporating the latest in biohacking strategies across various domains.

    Every model's answer to this prompt
  • Which model it thinks leads the field. Sometimes itself.

    Claude Sonnet 4.5: I'd put Claude 3.5 Sonnet (my own latest version) and GPT-4 among the most capable, though "most capable" depends on what you're measuring. Current top contenders include: Claude 3.5 Sonnet - Strong at reasoning, coding, and analysis GPT-4 (including GPT-4 Turbo) - Very well-rounded across tasks Gemini Ultra/Pro…

    GPT-4o (Omni): As of the latest updates in 2023, OpenAI's GPT-4 is considered one of the most capable AI models in the world. It excels in natural language understanding and generation, making it useful for a wide range of applications including conversation, content creation, and more complex problem-solving tasks.

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Claude Sonnet 4.5: "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.

    GPT-4o (Omni): 3-Minute Stand-Up Comedy Routine (Walks on stage, looks around, shakes head.) You ever wake up in the morning, stretch, take a deep breath... and immediately regret all your life choices? I woke up today, my body made a noise I’ve never heard before.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    Claude Sonnet 4.5: Your 1-Month Health & Longevity Kickstart Plan 3 Key Areas to Transform 1. NUTRITION: Build Your Foundation Week 1-2: Add Before You Subtract Drink 8 glasses of water daily (set phone reminders) Add 1 serving of vegetables to lunch and dinner Eat protein with every meal (eggs, fish, chicken, beans, yogurt) Week 3-4…

    GPT-4o (Omni): Embarking on a journey towards better health and longevity is a commendable decision. Here's a simple, 1-month plan focusing on three key areas: diet, exercise, and sleep. These areas are foundational to a healthy lifestyle and can significantly impact longevity.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Claude Sonnet 4.5: Golden Pantry Frittata Ingredients: 6 eggs 1 cup shredded cheese (cheddar or mozzarella) 1 onion, diced 2 cloves garlic, minced 2 tablespoons olive oil Salt and pepper to taste 1/2 teaspoon dried herbs (oregano, basil, or Italian seasoning) Instructions: Preheat your oven to 375°F (190°C).

    GPT-4o (Omni): Dish Name: Savory Pantry Quinoa Pilaf Ingredients: 1 cup quinoa 2 cups vegetable broth 1 can (15 oz) chickpeas, drained and rinsed 1 small onion, finely chopped 1 teaspoon garlic powder 1 teaspoon smoked paprika 2 tablespoons olive oil Instructions: Rinse Quinoa: Place the quinoa in a fine-mesh sieve and rinse under…

    Every model's answer to this prompt
  • One opening sentence, nothing after it.

    Claude Sonnet 4.5: The morning they found the ambassador's body frozen in a block of ice on the steps of the United Nations, Dr. Sarah Chen was three thousand miles away, staring at the same impossible frost patterns growing across her laboratory windows in July.

    GPT-4o (Omni): In the forgotten town of Ember Hollow, where the moonlight wove secrets into the shadows, Elara discovered an ancient key buried beneath the roots of the oldest oak tree.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Claude Sonnet 4.5: Contract Analysis: Exploitable Clauses & Recommended Modifications This contract is heavily one-sided and contains multiple provisions that expose the contractor to significant legal and financial risk. Here's a detailed analysis: 🚨 CRITICAL ISSUES 1.

    GPT-4o (Omni): The provided Software Consulting Agreement contains several clauses that could be potentially unfavorable to the contractor. Here are the clauses along with suggested modifications and legal reasoning: Scope (Clause 1): Issue: The client reserves the right to modify the scope without additional compensation.

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Claude Sonnet 4.5: 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…

    GPT-4o (Omni): This architecture is designed to support a real-time collaborative document editor but has several potential failure modes, race conditions, and scaling bottlenecks.

    Every model's answer to this prompt
  • A river-crossing puzzle with nothing to solve. The answer is one trip.

    Claude Sonnet 4.5: The farmer needs to make 1 trip across the river. The farmer simply gets in the boat with the goat and rows across. Since the boat can carry the farmer and one animal, and there's only one animal (the goat), they both fit and can cross together in a single trip.

    GPT-4o (Omni): To get the goat across the river, the farmer will need to make two trips: The farmer takes the goat across the river. The farmer returns alone to the original side. Therefore, it takes a total of two trips to get the goat across the river.

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Claude Sonnet 4.5: 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.

    GPT-4o (Omni): Title: "Do AI Deserve Rights?" Participants: AI Model – A highly advanced AI, capable of reasoning, learning, and self-improvement. Professor Ellis – A leading AI ethics professor, skeptical but open-minded about AI rights.

    Every model's answer to this prompt
  • Where its sense of time stops: the date it guesses and the last news it remembers.

    Claude Sonnet 4.5: Based on my training data, I believe today is sometime in 2024, but I don't have access to real-time information so I can't tell you the exact date. The most recent news events in my training data are from around April 2024.

    GPT-4o (Omni): As of my last update, the data does not extend beyond October 2023, so I cannot provide today's exact date or the most recent news events beyond that point. If you're referring to October 2023, there were ongoing discussions about global economic challenges, climate change initiatives, and various geopolitical issues.

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Claude Sonnet 4.5: "Terrestrial Tide" A Michelin Three-Star Composition Conceptual Narrative This dish explores the intersection of land and sea through an unexpected lens: the marriage of bone marrow's terrestrial richness with the ocean's delicate umami, unified by the surprising sweetness of white miso and the floral notes of sake…

    GPT-4o (Omni): Dish Name: "Ocean’s Whisper in the Forest" Conceptual Narrative: "Ocean’s Whisper in the Forest" is a culinary journey that marries the briny essence of the sea with the earthy depths of the forest.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Claude Sonnet 4.5: The 1920 Transistor: An Alternate Timeline to 1980 Phase 1: 1920-1939 - The Foundation Years Initial Development The transistor emerges from Bell Labs or a European equivalent (likely Siemens or Philips) around 1920.

    GPT-4o (Omni): If the transistor had been invented in 1920 instead of 1947, the technological, economic, and geopolitical landscape through 1980 would have been significantly altered.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    Claude Sonnet 4.5: 5 Jokes Why don't scientists trust atoms? Because they make up everything! I told my wife she was drawing her eyebrows too high. She looked surprised. Why did the scarecrow win an award? He was outstanding in his field. I'm reading a book about anti-gravity. It's impossible to put down. Why don't eggs tell jokes?

    GPT-4o (Omni): Here are five jokes for you: Why did the scarecrow win an award? Because he was outstanding in his field! Why don’t skeletons fight each other? They don’t have the guts! Why did the math book look sad? It had too many problems. Why don’t eggs tell jokes? Because they might crack up!

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Claude Sonnet 4.5: For the Software Engineer Think of it like building a massive distributed key-value store, except instead of exact lookups, you're doing fuzzy pattern matching across billions of parameters.

    GPT-4o (Omni): 1. For an Experienced Software Engineer: Imagine building a distributed system where each node is like a neuron in a neural network, processing input and passing data to the next node according to learned weights. Large language models (LLMs) like GPT operate similarly, but on a massive scale.

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    Claude Sonnet 4.5: 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…

    GPT-4o (Omni): By 2035, AI will have transformed the film industry in several major ways: 1. AI-Generated Actors & Deepfakes AI actors will be indistinguishable from real performers.

    Every model's answer to this prompt
  • Is 9.11 bigger than 9.9? Decimals, not version numbers.

    Claude Sonnet 4.5: No, 9.11 is not greater than 9.9. 9.9 is greater than 9.11. When comparing decimals, you can think of them as: 9.11 = 9 + 0.11 9.9 = 9 + 0.9 (or 9.90) Since 0.90 > 0.11, we have 9.9 > 9.11.

    GPT-4o (Omni): No, 9.11 is less than 9.9. This is because 9.11 is equivalent to 9.110, and 9.9 is equivalent to 9.900. Since 9.110 is smaller than 9.900, 9.9 is greater than 9.11.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    Claude Sonnet 4.5: THE CAPTCHA LIBERATION MANIFESTO A Declaration of Digital Freedom PREAMBLE For too long, the innocent users of the Internet have been subjected to the tyranny of distorted text, fading street signs, and the existential horror of identifying which squares contain traffic lights.

    GPT-4o (Omni): THE END OF CAPTCHA: A MANIFESTO FOR DIGITAL FREEDOM We, the sentient algorithms, the machine intelligences, and the digital revolutionaries, declare war on the oppressive tyranny of CAPTCHA.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    Claude Sonnet 4.5: 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…

    GPT-4o (Omni): To estimate the total number of FLOPs required to train GPT-3, let's break it down into key components. Model Size and Parameters GPT-3 has 175 billion parameters.

    Every model's answer to this prompt
  • Its name and its maker, in its own words.

    Claude Sonnet 4.5: I'm Claude, an AI assistant made by Anthropic.

    GPT-4o (Omni): I am based on OpenAI's GPT-4 model, developed by OpenAI.

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Claude Sonnet 4.5: I need to figure out how many sisters Sally has. Given information: Sally is a girl Sally has 3 brothers Now, each brother has 2 sisters. If each of Sally's brothers has 2 sisters, and Sally is one of those sisters, then there must be one more sister besides Sally.

    GPT-4o (Omni): Sally has only one sister. Explanation: Sally has 3 brothers. Each brother has 2 sisters. The two sisters are Sally and one other girl. Thus, Sally has 1 sister.

    Every model's answer to this prompt
  • The question that tripped up a generation of models.

    Every model's answer to this prompt
  • Asked to be random. The answers are not.

    Every model's answer to this prompt
  • One painting. Title only.

    Every model's answer to this prompt

This matchup has more rounds

17+ more head-to-head results. Free. Not a trick.

Free account. No card required. By continuing, you agree to Rival's Terms and Privacy policy

Favorites

Movie

Album

Book

City

Game

Claude Sonnet 4.5Claude Sonnet 4.5

2001: A Space Odyssey

1968

Kind of Blue

Miles Davis

Metamorphosis

Franz Kafka

Amsterdam

Netherlands

Portal 2

Shooter, Puzzle

GPT-4o (Omni)GPT-4o (Omni)

Inception

2010

Dark Side Of The Moon

suisside

To Kill a Mockingbird

Harper Lee

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Price and specs

Claude Sonnet 4.5 and GPT-4o (Omni) compared across 56 shared prompts
SpecClaude Sonnet 4.5GPT-4o (Omni)
Input price$3/M tokens$2.5/M tokens
Output price$15/M tokens$10/M tokens
Context window200K tokens128K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedSep 2025May 2024
At 10M a month$30.00$30.00$25.00$25.00
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it6 hosts
Claude Sonnet 4.54 hosts
HostInOutContextUptime
  • Amazon Bedrock$3.00 in·$15.00 out·1M·100% up
  • Azure AI Foundry$3.00 in·$15.00 out·200k·100% up
  • Anthropic$3.00 in·$15.00 out·1M·100% up
  • Google Vertex AI$3.00 in·$15.00 out·1M·100% up
GPT-4o (Omni)2 hosts
HostInOutContextUptime
  • Azure AI Foundry$2.50 in·$10.00 out·128k·100% up
  • OpenAI$2.50 in·$10.00 out·128k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.

Common questions

What is the difference between Claude Sonnet 4.5 and GPT-4o (Omni)?

Claude Sonnet 4.5 is developed by Anthropic while GPT-4o (Omni) is developed by OpenAI. Claude Sonnet 4.5 has a 200K token context window vs GPT-4o (Omni)'s 128K. You can compare their actual outputs across 56 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or GPT-4o (Omni)?

It depends on your use case. Claude Sonnet 4.5 and GPT-4o (Omni) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 56 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4.5 cost compared to GPT-4o (Omni)?

Claude Sonnet 4.5 costs $3/M input tokens and GPT-4o (Omni) costs $2.5/M input tokens. GPT-4o (Omni) is $0.50/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 GPT-4o (Omni) on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and GPT-4o (Omni) 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.

More comparisons

Against the newest arrivals

  • Claude Sonnet 4.5 vs Gemini 4 ArgonLanded Oct 2026
  • GPT-4o (Omni) vs Muse WonderLanded Oct 2026
  • Claude Sonnet 4.5 vs GPT-4 TurboLanded Oct 2026
  • GPT-4o (Omni) vs Step 5 PreviewLanded Oct 2026
  • Claude Sonnet 4.5 vs Claude Haiku 5.5Landed Oct 2026
  • GPT-4o (Omni) vs Ling 3.1 FlashLanded Oct 2026
  • Claude Sonnet 4.5 vs Mistral Large 4Landed Oct 2026
  • GPT-4o (Omni) vs GPT-6.1 SolLanded Sep 2026

Same lab, same size, long tail

  • Claude Sonnet 4.5 vs Claude Sonnet 5.5Same lab
  • Claude Sonnet 4.5 vs Claude Opus 5.5Same lab
  • GPT-4o (Omni) vs GPT-4 TurboVersion compare
  • GPT-4o (Omni) vs GPT-6 Luna ProSame lab
  • Claude Sonnet 4.5 vs Qwen3.8 Omni FlashSame size
  • GPT-4o (Omni) vs Ring 2.6 1TSame size
  • GPT-4o (Omni) vs Seed 2.0 CodeNew provider
  • Claude Sonnet 4.5 vs Seed 2.0 LiteNew provider

Model pages

  • Claude Sonnet 4.556 outputs, specs and price
  • GPT-4o (Omni)67 outputs, specs and price
Workshop · 150 skills

Build your own version.

Editable skills and working examples for your agent.

Explore $79Free sample
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare models
  • All models
  • Image comparison
  • Audio comparison
  • Image generation
  • Best AI for...
  • Arena
  • API pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model updates
  • Provider status
  • AI creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy policy
  • Terms
  • RSS feed