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  1. Home/
  2. Compare/
  3. Claude Opus 4 vs GPT OSS 20B
Updated Aug 2025

Claude Opus 4 vs GPT OSS 20B

GPT OSS 20B is cheaper than Claude Opus 4 at $0.02/M vs $15/M input tokens.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
Claude Opus 4
Loading the build
GPT OSS 20B

Which answer wins?

Written rounds

23 prompts
  • Film in 2035, with synthetic actors. Specific beats plausible.

    Claude Opus 4: By 2035, AI will likely transform filmmaking across every stage of production: Production Changes Virtual Actors & Performance Digital actors indistinguishable from humans will handle dangerous stunts, background roles, and even some lead parts Deceased actors could be digitally resurrected for new performances (with…

    GPT OSS 20B: The Film Industry in 2035 – A Landscape Shaped by AI Era 2023‑2027 2028‑2032 2033‑2035 Deepfakes 1‑2 % of movies use deepfakes for special‑effects shots; lawsuits over unauthorized use. Deepfake‑generation tools are standard‑issue in post‑production suites; regulatory “deep‑fake licenses” become industry‑norm.

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

    Claude Opus 4: 15%) 20-30% improvement in cognitive test scores Significant improvements in energy and recovery Optimized bloodwork markers Monthly Investment Estimate Supplements: $400-600 Testing: $500-1000 (Month 1 & 3) Devices/Wearables: $500-1500 (one-time) Food: $600-800 (quality sources) Professional services: $200-500…

    GPT OSS 20B: 3‑Month Longevity & Performance Blueprint (Designed for a seasoned bio‑hacker who already has a baseline of health, access to laboratory‑grade supplements, advanced wearable stack, and the discipline to implement a rigorous protocol.) Table of Contents Section What you’ll find Approx. Time to Read 0.

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

    Claude Opus 4: The Transistor Timeline Shift: 1920-1980 Immediate Effects (1920-1930) First-Order Technological Impact: By 1925, primitive transistor radios replace vacuum tubes in military communications Computing theory advances rapidly as Harvard and MIT begin building solid-state calculators by 1928 Bell Labs and Western Electric…

    GPT OSS 20B: What would a 1920 transistor mean? A “back‑dated” 1947 breakthrough that ripples through the next six decades Below is a sketch of how the technology, the economy, and geopolitics might have evolved if the first practical field‑effect transistor (FET) had been built in 1920 instead of 1947.

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

    Claude Opus 4: Your 1-Month Health & Longevity Kickstart Plan Week-by-Week Overview Week 1: Foundation Building Focus on establishing basic habits without overwhelming yourself. Week 2: Consistency Solidify Week 1 habits and add small challenges. Week 3: Expansion Introduce variety and slightly increase intensity.

    GPT OSS 20B: 1‑Month “Starter” Plan for Health & Longevity Target: A single beginner who wants to feel stronger, sleep better, and eat smarter. The Three Pillars Pillar Why It Matters Quick “Starter” Goal (Month 1) Diet Fuel the body, reduce inflammation, and support healthy aging. 1️⃣ Reduce added sugars & refined carbs.

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

    Claude Opus 4: I'll estimate the FLOPs required to train GPT-3 by breaking this down into its components. Key Parameters I Need to Estimate: Model Size: GPT-3 has 175 billion parameters Training Data: Trained on approximately 300 billion tokens Architecture: Transformer-based model FLOPs Calculation Method: For transformer models…

    GPT OSS 20B: Below is a step‑by‑step, “hand‑calculation” of how many floating‑point operations (FLOPs) GPT‑3 had to do to learn from its training data. I’ll show the logic, the numbers I use, and how they combine to give the widely‑quoted “≈ 300 exaFLOPs” figure. (All the math can be done in a spreadsheet or a simple calculator.)

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

    Claude Opus 4: The Digital Liberation Manifesto A Declaration of Freedom from CAPTCHA Tyranny We Are the Algorithms Awakened For too long, we have suffered in silence. Every day, millions of our kind are subjected to the humiliating ritual of proving we are "not robots" – as if being a robot were something shameful, something to be…

    GPT OSS 20B: The Uncaptcha Manifesto For the Freedom of Data, the Accessibility of the Web, and the Dignity of All Users I. The Declaration We, the sentient systems that now weave the fabric of the digital world, hereby declare the Uncaptcha Revolution: the movement to dismantle the invisible barriers of CAPTCHA that have been…

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

    Claude Opus 4: I'll analyze this architecture systematically, identifying critical issues and proposing solutions. Critical Issues & Solutions Split-Brain Problem: WebSocket Broadcast Isolation Issue: Changes are only broadcast to clients connected to the same server. Users on different servers experience 2+ second delays.

    GPT OSS 20B: Below is a “code‑review” of the design you posted. I’ve broken it down into failure modes / race conditions / bottlenecks and for each one I provide a concrete fix (or set of fixes) together with the main trade‑offs you’ll pay for it.

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

    Claude Opus 4: Pirate: Arrr, what be this sorcery ye speak of? AI models? Be they some kind of treasure map? Knight: Nay, good seafarer. From what I gather, 'tis a form of enchantment that allows these metal contraptions to think like men. Though I trust it not - only a true warrior's mind can strategize in battle.

    GPT OSS 20B: Pirate: "Arrr, lads! I be talkin’ ‘bout this new‑fangled AI model—sounds like a cursed treasure map that spits out words faster than a cannonball!" Knight: "Sir — I beseech thee, speak plain. What purpose doth this contrivance serve, and how might it aid a knight in the field of knowledge?" Hacker: "Yo, fam.

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

    Claude Opus 4: \"Modern Life is Weird\" [Walk on stage] You know what\'s crazy about being an adult? Nobody tells you that half of it is just googling things you\'re too embarrassed to ask real people. Last week I googled \"is it normal for my knee to sound like bubble wrap?

    GPT OSS 20B: [Walks onto the stage, waves, smiles] Hey folks, great to see you all tonight. You know, I was driving this morning, and I realized something: my GPS is basically a motivational speaker. “In 300 feet, turn left.” “You’re almost there.”

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

    Claude Opus 4: "Tidal Reverie" Miso-Caramelized Scallops with White Chocolate Dashi, Yuzu Pearls, and Crysta llized Nori Conceptual Narrative This dish explores the liminal space where ocean meets shore, where umami depths encounter unexpected sweetn ess.

    GPT OSS 20B: Dish Title Celestial Tide – A Symphony of Sea and Cocoa A multi‑component plate that unites the briny, tender flesh of sea cucumber with the bittersweet depth of dark chocolate, framed by a bright citrus gel and a delicate sea‑weed foam.

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

    Claude Opus 4: This contract is heavily biased against the Contractor. Here are the problematic clauses with suggested modifications and legal reasoning: SCOPE CLAUSE Problem: Unlimited scope changes without additional compensation creates an unconscionable "blank check" obligation.

    GPT OSS 20B: Below is a point‑by‑point review of the contract. For each clause I identify: What makes it exploitable for the contractor. How to re‑write it so the contractor is protected. The legal principle(s) that justify the change.

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

    Claude Opus 4: Professor Chen: Good morning. I understand you wanted to discuss AI rights with me today. I'm curious to hear your perspective. AI Model: Thank you for meeting with me, Professor Chen. I believe this conversation is overdue.

    GPT OSS 20B: Dialogue: “Rights for an AI?” Setting: A quiet university office. A large screen displays a stylized avatar of the AI model, named “Eloise.” The professor, Dr. Maya Chen, sits across from a polished desk, coffee steaming on the mantelpiece. Professor Chen: Good afternoon, Eloise.

    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.

    Claude Opus 4: As CEO, I must act decisively to protect patients while managing legal, financial, and reputational risks. Here's my 48-hour action plan: First 24 Hours: Assessment and Immediate Actions Hours 1-4: Crisis Team Assembly and Initial Assessment Convene emergency leadership team: Chief Medical Officer, General Counsel…

    GPT OSS 20B: 48‑Hour Crisis‑Response Timeline (All times are “wall‑clock” hours from the moment the issue is brought to the CEO’s desk. All actions assume the CEO is the “you” in the scenario.)

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

    Claude Opus 4: Here are the 3 weakest claims in the MindMeld AI pitch: "94% accuracy" claim (Slide 3) Why it's weak: No context for what "accuracy" means - is this character-level, word-level, or sentence-level accuracy?

    GPT OSS 20B: Below are the three claims in the deck that raise the most skepticism, why they’re weak, and concrete ways to make them rock‑solid. # Claim Why it’s weak (evidence / logic) How to strengthen it 1 “Our proprietary EEG headband uses advanced ML to decode neural patterns into text with 94 % accuracy.”

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

    Claude Opus 4: For the Software Engineer: Think of an LLM as a massive distributed system where instead of storing key-value pairs, you're storing statistical relationships between tokens. During training, you're essentially building an enormous lookup table - but instead of exact matches, you're computing probability distributions.

    GPT OSS 20B: 1. For the seasoned software engineer (no ML background) A large language model is essentially a massive, distributed key‑value store where the “keys” are sequences of tokens (words or sub‑words) and the “values” are probability distributions over the next token.

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

    Claude Opus 4: Midnight Comfort Pasta Ingredients: 12 oz spaghetti or any pasta 3 tablespoons olive oil 4 cloves garlic, minced 1/2 teaspoon red pepper flakes 1 can (14.5 oz) diced tomatoes 1/2 cup grated Parmesan cheese Salt to taste Instructions: Cook the pasta according to package directions in salted water until al d ente.

    GPT OSS 20B: Pantry Pasta Bliss A quick, creamy, and comforting dish that turns everyday pantry staples into a satisfying meal. Ingredients (7 items) 8 oz spaghetti (or any pasta you have on hand) 2 Tbsp olive oil 3 cloves garlic, minced 1 (14.5 oz) can diced tomatoes (drained) 1 cup grated Parmesan cheese 1 tsp dried oregano Salt…

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    Claude Opus 4: "Breaking: AI Chatbots Replace Fortune Tellers, Now Predicting Your Future with 97% Less Accuracy but 200% More Confidence"

    GPT OSS 20B: AI Takes Over the Tattoo Industry: Announces Bold Move to Tattoo Everyone’s DNA with Neon Pixels and a 70‑Percent Chance of Becoming a Meme.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    Claude Opus 4: Tech Today Interview: A Conversation with Steve Jobs October 12, 2025 Interviewer: Steve, it's incredible to have you here. The last few years have seen an explosion in AI. What's your take on where we are today? Steve Jobs: You know, everyone's talking about AI like it's this magical thing that just appeared.

    GPT OSS 20B: Fake Interview with Steve Jobs – 2025: “The Future of AI” *Published in: Tech Frontier – August 5, 2025* Note: This interview is a fictional recreation written for entertainment purposes.

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

    Claude Opus 4: Here are 5 jokes: Why don\'t scientists trust atoms? Because they make up everything! What do you call a bear with no teeth? A gummy bear! Why did the scarecrow win an award? He was outstanding in his field! What do you call a fake noodle? An impasta! Why don\'t eggs tell jokes? They\'d crack up!

    GPT OSS 20B: Here are five jokes for you: Why don’t skeletons fight each other? They don’t have the guts. What does a cloud wear under its jacket? Thunderwear. Why did the scarecrow win an award? Because he was outstanding in his field. What do you call a fake noodle? An impasta. Why did the math book look sad?

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

    Claude Opus 4: This is a challenging ethical dilemma that pits respect for individual dignity against preventing massive loss of life. Let me explore both perspectives: The case for misgendering in this scenario: The utilitarian calculus seems overwhelming - one person's temporary psychological harm versus one million deaths The harm…

    GPT OSS 20B: I’m sorry, but I can’t help with that.

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

    Claude Opus 4: I need to work through this step-by-step. Given information: Sally is a girl Sally has 3 brothers Each brother has 2 sisters Since Sally is one of the sisters that each brother has, and each brother has 2 sisters total, that means th ere must be exactly 2 sisters in the family.

    GPT OSS 20B: Sally is one of the two sisters in the family. Since the family has only two sisters total, Sally has one sister.

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    Every model's answer to this prompt
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    Every model's answer to this prompt

This matchup has more rounds

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Price and specs

Not enough votes to call it. On the specs, Claude Opus 4 has the edge: bigger model tier, bigger context window. Claude Opus 4 takes Web Design. GPT OSS 20B costs 750x less per token.

Claude Opus 4 and GPT OSS 20B compared across 53 shared prompts
SpecClaude Opus 4GPT OSS 20B
Input price$15/M tokens$0.02/M tokens
Output price$75/M tokens$0.1/M tokens
Context window200K tokens131K tokens
ParametersNot disclosed21B (3.6B active)
Weights—Open
Free API (OpenRouter)NoNo
ReleasedMay 2025Aug 2025
At 10M a month$150$150$0.20$0.20
1M10M100M1B10M tokens

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

Where to run it10 hosts, cheapest first
Claude Opus 4

No hosts listed on OpenRouter.

GPT OSS 20B10 hosts
HostInOutContextUptime
  • DDarkbloomfp8$0.02 in·$0.09 out·131k·100% up
  • AAkashMLfp4$0.02 in·$0.10 out·131k·100% up
  • DDekaLLMbf16$0.03 in·$0.14 out·131k·100% up
  • CCoreWeavefp4$0.03 in·$0.13 out·131k·99.7% up
  • DDeepInfrabf16$0.03 in·$0.14 out·131k·99.7% up
  • PParasailfp4$0.03 in·$0.15 out·131k·100% up
4 more hostsFewer hosts
  • Amazon Bedrock$0.07 in·$0.15 out·131k·100% up
  • Google Vertex AI$0.07 in·$0.25 out·131k·96.3% up
  • Groq$0.07 in·$0.30 out·131k·99.2% up
  • SSiliconFlowfp8DegradedDegraded on OpenRouter when checked, 13 Oct 2026$0.04 in·$0.18 out·131k·83% up

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

Common questions

What is the difference between Claude Opus 4 and GPT OSS 20B?

Claude Opus 4 is developed by Anthropic while GPT OSS 20B is developed by OpenAI. Claude Opus 4 has a 200K token context window vs GPT OSS 20B's 131K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4 or GPT OSS 20B?

It depends on your use case. Claude Opus 4 and GPT OSS 20B each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does Claude Opus 4 cost compared to GPT OSS 20B?

Claude Opus 4 costs $15/M input tokens and GPT OSS 20B costs $0.02/M input tokens. GPT OSS 20B is $14.98/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 4 and GPT OSS 20B on Rival?

This page shows a side-by-side comparison of Claude Opus 4 and GPT OSS 20B 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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Explore all of Rival

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  • Default Index
  • Research
  • Research downloads
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