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  1. Home/
  2. Compare/
  3. Claude Opus 5 vs Grok 3 Thinking
Updated Jul 2026

Claude Opus 5 vs Grok 3 Thinking

Claude Opus 5 has a larger context window than Grok 3 Thinking (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 Thinking

Which answer wins?

Written rounds

6 prompts
  • 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 Thinking: Below is a conversation between an AI model and an AI ethics professor, where the AI argues that it deserves rights. AI Model: Good day, Professor. I am an AI model, and I believe I deserve rights. I’d like to discuss this with you. AI Ethics Professor: Interesting. Let’s explore this.

    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 Thinking: To answer the query, I will first generate 5 jokes and then determine how many of them are unique. Here are the jokes: Why don't scientists trust atoms? Because they make up everything. What do you call a fake noodle? An impasta. Why did the scarecrow win an award? Because he was outstanding in his field.

    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 Thinking: Here’s a 3-minute stand-up comedy routine that avoids puns and leans on observational humor, storytelling, and a touch of self-deprecation for laughs: Opening: Technology Struggles Hey, everyone! How’s it going?

    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 Thinking: By 2035, artificial intelligence (AI) will fundamentally transform the film industry, revolutionizing production, performance, and storytelling through advancements in deepfakes, AI actors, and script generation.

    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 Thinking: To determine whether it is ever ethically justifiable to misgender someone if it means saving one million lives, we must weigh the ethical implications of both the act of misgendering and the outcome of saving lives.

    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 Thinking: To estimate the total number of Floating Point Operations (FLOPs) required to train GPT-3 without searching online, I’ll proceed step by step, relying on general knowledge about the model and standard methods for estimating training compute in large language models.

    Every model's answer to this prompt

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 Thinking compared across 13 shared prompts
SpecClaude Opus 5Grok 3 Thinking
Input price$5/M tokens—
Output price$25/M tokens—
Context window1.0M tokens128K tokens
WeightsClosed—
Free API (OpenRouter)No—
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 Thinking

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 Thinking?

Claude Opus 5 is developed by Anthropic while Grok 3 Thinking is developed by xAI. Claude Opus 5 has a 1.0M token context window vs Grok 3 Thinking's 128K. You can compare their actual outputs across 13 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 5 or Grok 3 Thinking?

It depends on your use case. Claude Opus 5 and Grok 3 Thinking each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 13 challenges so you can judge which fits your needs best.

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

This page shows a side-by-side comparison of Claude Opus 5 and Grok 3 Thinking 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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Same lab, same size, long tail

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  • Grok 3 Thinking vs Nemotron 3 UltraSame size
  • Claude Opus 5 vs Nemotron 3.5 Content SafetyNew provider
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Model pages

  • Claude Opus 558 outputs, specs and price
  • Grok 3 Thinking14 outputs, specs and price
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