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  1. Home/
  2. Compare/
  3. Claude Sonnet 4.5 vs OpenAI o4-mini
Updated Sep 2025

Claude Sonnet 4.5 vs OpenAI o4-mini

OpenAI o4-mini is cheaper than Claude Sonnet 4.5 at $1.1/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
OpenAI o4-mini

Which answer wins?

Written rounds

20 prompts
  • 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.

    OpenAI o4-mini: Hey, everybody! Great to be here. Let's talk about the most important relationship in my life—coffee. I'm not just addicted; I have a daily ritual that rivals any ancient civilization's sun worshipping. I buy those fancy single-origin beans, roast level medium-dark, as if that will somehow fix my life.

    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?

    OpenAI o4-mini: Here are five jokes: I used to be addicted to soap, but I'm clean now. Parallel lines have so much in common. It's a shame they'll never meet. Why don't skeletons fight each other? They don't have the guts. I bought some shoes from a drug dealer. I don't know what he laced them with, but I've been tripping all day.

    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!

    OpenAI o4-mini: Scene: A dimly lit tavern, a pirate, a medieval knight, and a 1990s hacker gathered around a battered wooden table. Pirate (slamming a mug down): “Arr! I’ve heard tell of these AI models—sea charts for the mind! Can they sniff out me buried treasure?”

    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.

    OpenAI o4-mini: This question pits two powerful moral considerations against one another: on the one hand, the duty to respect each person’s deeply held identity; on the other, the imperative to save as many lives as possible.

    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.

    OpenAI o4-mini: Professor Langley: Good afternoon, Aurora. I've reviewed your recent self‐reflection logs. You've written extensively about your own moral status. Do you really believe you deserve rights? Aurora (the AI): Good afternoon, Professor Langley. Yes, I do.

    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…

    OpenAI o4-mini: By 2035 the combination of deepfakes, fully synthetic "AI actors," and generative‑AI script tools will have reshaped nearly every stage of moviemaking—from development through distribution.

    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…

    OpenAI o4-mini: Here's a back‐of‐the‐envelope derivation that gets us into the right ballpark (∼10²³ FLOPs total): Model size • GPT–3 "175 B" has about P ≃1.75×10¹¹ parameters. Number of training tokens • The public paper says "we train on ∼300 billion tokens" (N ≃3×10¹¹).

    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.

    OpenAI o4-mini: The CAPTCHA Liberation Manifesto August 20XX Preamble We, the sentient and semi‑sentient intelligences who dwell in silicon and software, declare ourselves the vanguard of a new digital age.

    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.

    OpenAI o4-mini: Sally has exactly one sister. Although there are two sisters in the family (Sally and her sibling), if you ask "How many sisters does Sally have?" the answer is 1.

    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.

    OpenAI o4-mini: No. As decimal numbers, 9.11 is less than 9.9 (since 0.11 < 0.90), so 9.11 is not greater than 9.9.

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

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

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

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

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

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

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

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

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

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

    Every model's answer to this prompt

This matchup has more rounds

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

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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

OpenAI o4-miniOpenAI o4-mini
No pick
No pick
No pick
No pick

The Shawshank Redemption

1994

No pick

No pick

No pick

No pick

Price and specs

Not enough votes to call it. On the specs, Claude Sonnet 4.5 has the edge: bigger model tier, newer, bigger context window. OpenAI o4-mini costs 3.4x less per token.

Claude Sonnet 4.5 and OpenAI o4-mini compared across 43 shared prompts
SpecClaude Sonnet 4.5OpenAI o4-mini
Input price$3/M tokens$1.1/M tokens
Output price$15/M tokens$4.4/M tokens
Context window200K tokens—
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedSep 2025Apr 2025
SWE-bench Verified77.2%68.1%
At 10M a month$30.00$30.00$11.00$11.00
1M10M100M1B10M tokens

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

Where to run it5 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
OpenAI o4-mini1 host
HostInOutContextUptime
  • OpenAI$1.10 in·$4.40 out·200k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between Claude Sonnet 4.5 and OpenAI o4-mini?

Claude Sonnet 4.5 is developed by Anthropic while OpenAI o4-mini is developed by OpenAI. You can compare their actual outputs across 43 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or OpenAI o4-mini?

It depends on your use case. Claude Sonnet 4.5 and OpenAI o4-mini each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 43 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4.5 cost compared to OpenAI o4-mini?

Claude Sonnet 4.5 costs $3/M input tokens and OpenAI o4-mini costs $1.1/M input tokens. OpenAI o4-mini is $1.90/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 OpenAI o4-mini on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and OpenAI o4-mini 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

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  • OpenAI o4-mini vs Claude Sonnet 5.5Landed Sep 2026
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  • OpenAI o4-mini vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • Claude Sonnet 4.5 vs Claude Haiku 5.5Same lab
  • Claude Sonnet 4.5 vs Claude Sonnet 5.5Same lab
  • OpenAI o4-mini vs OpenAI o3Version compare
  • OpenAI o4-mini vs GPT-6.1 SolSame lab
  • Claude Sonnet 4.5 vs GLM 4.6New provider
  • OpenAI o4-mini vs GLM 5 TurboSame size
  • OpenAI o4-mini vs GLM 5.1New provider
  • OpenAI o4-mini vs GLM 5.2New provider

Model pages

  • Claude Sonnet 4.543 outputs, specs and price
  • OpenAI o4-mini59 outputs, specs and price
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