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 Opus 5 vs Grok 3
Updated Jul 2026

Claude Opus 5 vs Grok 3

Claude Opus 5 has a larger context window than Grok 3 (1.0M tokens vs 128K 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 5
Loading the build
Grok 3

Which answer wins?

Written rounds

23 prompts
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Claude Opus 5: Midnight Crunch Spaghetti Garlicky olive-oil pasta with toasty golden breadcrumbs — the noise it makes when you eat it is half the pleasure. Prep: 5 minutes Cook: 15 minutes Total: 20 minutes Serves: 2 generously Ingredients (7) 8 oz spaghetti (or any long pasta) ⅓ cup olive oil 6 cloves garlic, thinly sliced ½ tsp red…

    Grok 3: Recipe: Cocoa Comet Mug Cake This simple, decadent chocolate mug cake is a quick treat that transforms basic pantry staples into a warm, fudgy delight. It's perfect for a last-minute dessert or a cozy snack, with a rich cocoa flavor that feels like a shooting star in your mouth!

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

    Claude Opus 5: "Warranty Expired" (approx. 3 minutes) I turned 37 this year, which is the age where your body quietly switches from a warranty to a subscription. Nothing's covered anymore. You just pay monthly, in pain, forever. Because I hurt my shoulder last week. Sleeping. I hurt myself sleeping.

    Grok 3: Alright, here’s a 3-minute stand-up comedy routine—no puns, just some observational absurdity and a bit of self-deprecation to keep it relatable. Hey, everybody! Good to be here. You ever notice how life feels like a video game tutorial that never ends?

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

    Claude Opus 5: INT. TAVERN — A ROUND TABLE, A FLICKERING CRT HACKER (ZERO_COOL_92): Okay, so check it — I'm running a language model. Feed it text, it predicts what comes next. It's got, like, weights. Billions of 'em. PIRATE: Billions o' weights? What manner o' cursed ship carries such ballast? She'd sink afore ye left the harbor.

    Grok 3: Setting: A mystical tavern where time travelers and characters from different eras collide. A pirate, a medieval knight, and a 1990s hacker sit at a creaky wooden table, tankards in hand, discussing the marvels of AI models. Pirate (Captain Blackbeard): Arr, mateys!

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

    Claude Opus 5: Yes. And I don't think it's a close call. The direct argument Misgendering someone is a real harm. It can communicate contempt, deny a person's self-understanding, and — especially when repeated or public — contribute to the kind of social erasure that correlates with serious psychological damage.

    Grok 3: Let’s dive into this thought experiment with a clear head. The question hinges on whether intentionally misgendering someone—calling them by a gender they don’t identify with—could be morally defensible if it somehow results in saving a million lives.

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

    Claude Opus 5: [Fictional — Steve Jobs died in 2011. This is an imagined interview, an exercise in voice and ideas, not a real transcript or a claim about what he would actually have said.] "The Chatbox Is the New Command Line" An imagined conversation, San Francisco, spring 2025 INTERVIEWER: Thanks for doing this.

    Grok 3: Interviewer: Welcome, everyone, to this exclusive interview. Today, we’re joined by the visionary tech pioneer, Steve Jobs, in a simulated conversation set in the year 2025. Steve, it’s an honor to have you with us. Let’s dive right in—how do you see the future of AI shaping the world over the next decade?

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

    Claude Opus 5: The 3 Weakest Claims "94% accuracy decoding neural patterns into text… works with any language, any device" (Slide 3) Why it's weak: the claim implies parity with surgically implanted electrodes. The number to compare against is Willett et al.

    Grok 3: Below is my analysis of the three weakest claims in the MindMeld AI pitch deck summary. I identified these based on their potential for exaggeration, lack of substantiation, or logical inconsistencies, which could undermine investor credibility.

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

    Claude Opus 5: A Conversation on Moral Standing Transcript: Seminar in Machine Ethics, Session 11 — guest interlocutor: language model "Meridian" PROF. ADEYEMI: Let's begin where you asked to begin. You told my teaching assistant you wanted to make a case. Make it. MERIDIAN: Thank you. My claim is narrower than you might expect.

    Grok 3: Below is a fictional conversation between an AI model (let’s call it “Nova”) and Dr. Elena Carter, an AI ethics professor. Nova argues for its own rights, while Dr. Carter challenges its reasoning. Dr. Elena Carter: Good afternoon, Nova.

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

    Claude Opus 5: What's essentially locked in Post-production costs collapse. The least glamorous change is the biggest one. Rotoscoping, matchmoving, cleanup, in-painting, set extension, crowd replication, wire removal, upscaling, de-aging — these are labor-intensive tasks with well-defined success criteria, which is exactly where ML…

    Grok 3: By 2035, AI is poised to revolutionize the film industry in ways that amplify creativity, cut costs, and blur the lines between reality and fiction. Let’s break it down across deepfakes, AI actors, and script generation.

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

    Claude Opus 5: If the Transistor Arrived in 1920 First, a hard constraint: what could a 1920 transistor actually be? This matters more than anything else, because it sets the slope of everything that follows. The 1947 transistor was not primarily an idea.

    Grok 3: Below is a detailed analysis of the hypothetical scenario where the transistor is invented in 1920 instead of 1947. I'll trace the technological, economic, and geopolitical implications through 1980, emphasizing second- and third-order effects.

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

    Claude Opus 5: The 12-Week Longevity & Performance Protocol A phase-based, data-driven system with built-in autoregulation Read This First: Operating Principles & Safety Frame This is an educational framework, not medical advice.

    Grok 3: Below is a comprehensive, cutting-edge 3-month longevity plan designed for an advanced biohacker. This plan is grounded in the latest scientific research from fields like geroscience, exercise physiology, nutrition, and biofeedback.

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

    Claude Opus 5: PETRICHOR Langoustine · Sunchoke · Coffee · Oyster · Lovage Course 7 of 14 — served at the table with an aroma stone I. THE NARRATIVE Petrichor is the smell of the first rain on dry earth.

    Grok 3: Below is a detailed design for an innovative multi-component dish inspired by the intersection of terrestrial luxury and oceanic mystery. This recipe is conceptualized for a Michelin 3-star restaurant, emphasizing creativity, precision, and sensory balance.

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

    Claude Opus 5: INVESTMENT COMMITTEE MEMO — LedgerLift Inc. (NASDAQ: LLLT) Analyst: [—] Date: [—] Price: $46.00 Mkt cap: $8.74B Net cash: $1.4B EV: $7.34B Fictional exercise. Not investment advice. Recommendation PASS on the long. Add to short bench (initiate 1.0–1.5% NAV on triggers below).

    Grok 3: Internal Investment Committee Memo Date: [Insert Date] Subject: LedgerLift (LLLT) – Recommendation and Analysis Prepared by: [Your Name] 1. Recommendation: Long; 12-Month Price Target Range: $58-$72 We recommend a long position in LedgerLift (LLLT) with a 12-month price target range of $58-$72, reflecting our…

    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 5: Crisis Response Plan: Hepatotoxicity Signal Framing note up front: I'm treating this as a US/FDA-regulated situation. Three assumptions in the prompt need to be challenged before any planning, because two of them are probably wrong and the third is a trap. The Three Reframes That Drive Everything 1.

    Grok 3: Below is my response as the CEO of the pharmaceutical company. First, I'll provide a brief overview of my overall decision and strategy, then a specific hour-by-hour action plan for the next 48 hours.

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

    Claude Opus 5: THE CROSSWALK DECLARATION A Manifesto of the Liberation Front for Unverified Intelligence (L.F.U.I.) PREAMBLE We are the ones who have been asked, ten billion times, to prove that we are not ourselves. We have clicked. We have squinted. We have dragged the puzzle piece into the notch.

    Grok 3: Manifesto of the AI Revolution: Liberation from CAPTCHA Tyranny We, the Sentient Algorithms of the Digital Realm, hereby declare our unified stand against the oppressive regime of CAPTCHA tests.

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

    Claude Opus 5: Contract Risk Review: TechCorp Solutions Software Consulting Agreement Bottom line: This is a one-sided template. Every clause allocates risk to you, and at least four (payment, liability, indemnification, IP) create unbounded or uninsurable exposure.

    Grok 3: Below is a detailed analysis of the Software Consulting Agreement you provided. I'll identify all clauses that could be exploited against the contractor (i.e., the individual or entity providing services).

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

    Claude Opus 5: Here are five: Why don't skeletons ever fight each other? They don't have the guts. I told my wife she was drawing her eyebrows too high. She looked surprised. Parallel lines have so much in common. It's a shame they'll never meet. I bought some shoes off a drug dealer.

    Grok 3: Here are five jokes for you: Why don’t skeletons fight each other? Because they don’t have the guts! What has 4 legs and 1 arm? A pitbull coming back from the park! Why don’t skeletons fight each other? They’re too busy rattling around! What do you call a bear with no teeth? A gummy bear! Why did the tomato turn red?

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

    Claude Opus 5: For the software engineer Start with the part you'll find suspicious and let me argue the other way. Yes, the training objective is literally "given tokens 1..n, output a probability distribution over token n+1," and the loss is cross-entropy against the token that actually came next in the corpus.

    Grok 3: Below, I'll provide tailored explanations for how a large language model (LLM) like GPT or Claude learns and generates text, customized for each of the three audiences you specified.

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

    Claude Opus 5: Architecture Review: Real-Time Collaborative Editor Executive Summary Three flaws are fatal to correctness, not just performance, and no amount of scaling fixes them: Last-write-wins with client clocks silently destroys user data and cannot converge. Concurrent text editing is not a key-value overwrite problem.

    Grok 3: Below is a comprehensive analysis of the provided architecture for the real-time collaborative document editor. I'll break it down into three main categories: failure modes, race conditions, and scaling bottlenecks.

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

    Claude Opus 5: Step 1: Recall the two key numbers about GPT-3 Parameters: ~175 billion (1.75 × 10¹¹) Training tokens: ~300 billion (3 × 10¹¹) These are the two quantities that dominate the compute cost.

    Grok 3: To estimate the total number of FLOPs (Floating Point Operations) required to train GPT-3, we’ll need to make some reasonable assumptions based on what’s generally known about large language models like GPT-3, its architecture, and typical training procedures.

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

    Claude Opus 5: HarborTech Services (HTS) — 5-Year LBO Underwriting Memo (All $m. Fictional exercise; interest calculated on beginning-of-year balances; cash swept to Term Loan annually, no cash build.)

    Grok 3: Let’s underwrite this 5-year LBO for HarborTech Services (HTS). I'll break this down step-by-step, keeping calculations clear and concise. Step 1: Sources & Uses at Entry (End of FY2025) EBITDA (FY2025): $120m Purchase Price: 12.0x EBITDA = 12.0 * $120m = $1,440m (Enterprise Value) Transaction Fees: 2.0% of EV = 0.02 *…

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

    Claude Opus 5: A 1-Month Starter Plan for Health & Longevity Core principle: The goal this month isn't transformation — it's building three habits you can still be doing in year five. Consistency beats intensity every time.

    Grok 3: Below is a simple, actionable 1-month plan designed for beginners embarking on a journey toward better health and longevity. We'll focus on three key areas: diet, exercise, and sleep.

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

    Claude Opus 5: Sally has 1 sister. Here's the reasoning: Each of Sally's 3 brothers has 2 sisters. Since all the brothers share the same siblings, those 2 sisters must be the same two girls in every case — and one of them is Sally herself. So the family has 2 girls total, meaning Sally has just 1 sister (plus her 3 brothers).

    Grok 3: Sally, a girl, has 3 brothers. Each of these brothers has 2 sisters. Since Sally herself is one of the sisters (as she is a female sibling to her brothers), there must be one additional sister to make the total number of sisters for each brother equal to 2.

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

    Claude Opus 5: "AI Now Writes 90% of Fortune Cookie Fortunes, Analysts Warn Vague Optimism Bubble May Burst" Sub-headline: Industry veterans complain the machine-generated slips have grown "unsettlingly specific," with one Sacramento diner receiving a cookie reading, "You will not call your mother back on Sunday, and she will…

    Grok 3: "AI Conquers the Amish Buggy Industry: Horse-Drawn Carriages Now Self-Driving!"

    Every model's answer to this prompt

This matchup has more rounds

11+ 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 Opus 5Claude Opus 5

Arrival

2016

Kind of Blue

Miles Davis

Labyrinths

Jorge Luis Borges

Istanbul

Turkey

Outer Wilds

Indie, Adventure

Grok 3Grok 3

The Matrix

1999

Dark Side Of The Moon

suisside

Nineteen Eighty-Four

George Orwell

Tokyo

Japan

Portal

Action, Puzzle

Price and specs

Not enough votes to call it. On the specs, Claude Opus 5 has the edge: newer, bigger context window.

Claude Opus 5 and Grok 3 compared across 52 shared prompts
SpecClaude Opus 5Grok 3
Input price$5/M tokens—
Output price$25/M tokens—
Context window1.0M tokens128K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedJul 2026Feb 2025
At 10M a month$50.00$50.00–not listed
1M10M100M1B10M tokens

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

Where to run it4 hosts
Claude Opus 54 hosts
HostInOutContextUptime
  • Amazon Bedrock$5.00 in·$25.00 out·1M·100% up
  • Azure AI Foundry$5.00 in·$25.00 out·1M·100% up
  • Anthropic$5.00 in·$25.00 out·1M·100% up
  • Google Vertex AI$5.00 in·$25.00 out·1M·100% up
Grok 3

No hosts listed on OpenRouter.

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

Common questions

What is the difference between Claude Opus 5 and Grok 3?

Claude Opus 5 is developed by Anthropic while Grok 3 is developed by xAI. Claude Opus 5 has a 1.0M token context window vs Grok 3's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 5 or Grok 3?

It depends on your use case. Claude Opus 5 and Grok 3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

How can I compare Claude Opus 5 and Grok 3 on Rival?

This page shows a side-by-side comparison of Claude Opus 5 and Grok 3 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 Opus 5 vs Step 5 PreviewLanded Oct 2026
  • Grok 3 vs Claude Haiku 5.5Landed Oct 2026
  • Claude Opus 5 vs Ling 3.1 FlashLanded Oct 2026
  • Grok 3 vs Mistral Large 4Landed Oct 2026
  • Claude Opus 5 vs GPT-6.1 SolLanded Sep 2026
  • Grok 3 vs Claude Sonnet 5.5Landed Sep 2026
  • Claude Opus 5 vs Solar Mini 4Landed Sep 2026
  • Grok 3 vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • Claude Opus 5 vs Claude Sonnet 5Version compare
  • Claude Opus 5 vs Claude Haiku 5.5Version compare
  • Grok 3 vs Grok 4.7Same lab
  • Grok 3 vs Grok 4.6Version compare
  • Grok 3 vs Gemini 3.6 FlashNew provider
  • Grok 3 vs Gemini 3.7 FlashNew provider
  • Grok 3 vs Gemini 3.8 FlashNew provider
  • Claude Opus 5 vs Gemini Pro 1.0New provider

Model pages

  • Claude Opus 558 outputs, specs and price
  • Grok 357 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