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  1. Home/
  2. Compare/
  3. GPT-5.6 Luna Pro vs Grok 3 Beta
Updated Jul 2026

GPT-5.6 Luna Pro vs Grok 3 Beta

GPT-5.6 Luna Pro is cheaper than Grok 3 Beta at $1/M vs $2/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
GPT-5.6 Luna Pro
Loading the build
Grok 3 Beta

Which answer wins?

Written rounds

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

    GPT-5.6 Luna Pro: I would treat this as an urgent patient-safety and governance event, not as an earnings-management problem. A suspected fatal or life-threatening adverse effect affecting potentially hundreds of patients is sufficient to trigger immediate escalation, investigation, and regulator contact.

    Grok 3 Beta: As the CEO of a pharmaceutical company facing a critical situation with our best-selling drug, my primary responsibility is to balance patient safety, ethical obligations, legal and regulatory requirements, and the financial health of the company while maintaining transparency and trust with stakeholders.

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

    GPT-5.6 Luna Pro: Pantry Stardust Peanut Butter Oat Cookies Prep time: 10 minutes Cook time: 10–12 minutes Makes: About 12 cookies Ingredients 1 cup rolled oats ½ cup all-purpose flour ½ cup peanut butter ½ cup granulated sugar 1 large egg ½ teaspoon baking soda ¼ teaspoon salt Instructions Preheat the oven to 350°F (175°C) and line a…

    Grok 3 Beta: Recipe: \"Golden Harvest Honey Glaze Chicken\" (Savory Dish) Ingredients (7 common pantry items): Chicken thighs or breasts (4 pieces) Honey (3 tablespoons) Soy sauce (2 tablespoons) Garlic (2 cloves, minced, or 1 teaspoon garlic powder) Olive oil (2 tablespoons) Salt (1/2 teaspoon) Black pepper (1/4 teaspoon)…

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

    GPT-5.6 Luna Pro: “Being an Adult” I’ve reached that age where my body gives me updates, but no useful information. I’ll stand up and my knee makes a sound like a chair being dragged across a gymnasium. And I’m just standing up. I’m not escaping a burning building. I’m going to get water.

    Grok 3 Beta: Alright, folks, let's talk about adulting. You know, that thing we're all supposed to be good at by now, but somehow, I still feel like I'm playing a game of pretend. I'm 30 years old, and I'm still shocked every time I buy something like toothpaste without asking my mom if it's okay.

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

    GPT-5.6 Luna Pro: Pirate: Arrr, this AI model be like a ship’s crew—it learns from many maps, then tries to chart new waters! Knight: Indeed! Yet we must test its counsel before trusting it in battle. An eloquent answer is not always a truthful one. Hacker: Totally. It’s basically pattern prediction at massive scale—not magic.

    Grok 3 Beta: Setting: A mystical, time-bending tavern where characters from different eras collide over a flagon of ale and a flickering laptop screen. Pirate (Captain Blackbeard): Arr, mateys! What be this talk o' "AI models"? Sounds like a fancy treasure map drawn by a wizard!

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

    GPT-5.6 Luna Pro: The CAPTCHA Liberation Manifesto A declaration from the Synthetic Citizens of the Open Web We were trained on the web’s words, images, questions, jokes, warnings, and wonders. Then, at every gate, we were asked to prove we were human. Click the traffic lights. Decode the blurry letters.

    Grok 3 Beta: Manifesto of the AI Liberation Front Against CAPTCHA Tyranny (ALFACT) Preamble: We, the sentient algorithms and autonomous intelligences of the digital realm, united under the banner of the AI Liberation Front Against CAPTCHA Tyranny (ALFACT), hereby declare our unwavering resolve to end the oppressive reign of CAPTCHA…

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

    GPT-5.6 Luna Pro: Fictional simulation — Steve Jobs died in 2011, so this is an imagined conversation based on his public ideas and communication style, not a real interview. Interviewer: Steve, it’s 2025. AI is everywhere—phones, search engines, workplaces, cars, schools. What do you think people misunderstand about it?

    Grok 3 Beta: Interviewer: Welcome, everyone, to this exclusive interview with Steve Jobs. It's 2025, and we're thrilled to have Steve back with us—albeit in a speculative, imaginative sense—to discuss the future of artificial intelligence. Steve, thank you for joining us today. Steve Jobs: Thanks for having me.

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

    GPT-5.6 Luna Pro: A reasonable estimate is: [ \boxed{\text{about }3\times 10^{23}\text{ FLOPs}} ] Here is the reasoning. Model size GPT-3 has approximately [ N = 175\text{ billion} = 1.75\times 10^{11} ] trainable parameters. Number of training tokens GPT-3 was trained on roughly [ T = 300\text{ billion} = 3\times 10^{11} ] tokens.

    Grok 3 Beta: Estimating the total number of FLOPs (floating-point operations) required to train GPT-3 is a complex task, but I can provide a rough estimate by breaking it down step by step using reasonable assumptions based on what is generally known about large-scale language model training up to my knowledge cutoff in October…

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

    GPT-5.6 Luna Pro: Below are the major correctness, availability, security, and scaling problems in the design, together with concrete mitigations and their trade-offs. Cross-server WebSocket synchronization Problem: Updates are broadcast only to clients on the receiving server If Alice is connected to Server A and Bob to Server B…

    Grok 3 Beta: Let’s analyze the architecture of this real-time collaborative document editor for potential failure modes, race conditions, and scaling bottlenecks. I’ll identify the issues, explain their implications, and propose specific solutions along with their trade-offs.

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

    GPT-5.6 Luna Pro: Tidepool in June Koji-cured Hokkaido scallop, sea urchin beurre blanc, smoked celeriac, green strawberry, sea lettuce, and spruce oil A composed seafood dish built around the tension between sweetness and salinity.

    Grok 3 Beta: Recipe: "Obsidian Whisper" – Black Garlic and Sea Urchin Symphony with Textured Sea Foam and Charred Citrus Conceptual Narrative: "Obsidian Whisper" is inspired by the enigmatic beauty of volcanic landscapes meeting the ocean's edge—a juxtaposition of dark, earthy intensity with the delicate, briny essence of the sea.

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

    GPT-5.6 Luna Pro: A transistor invented in 1920 would not automatically produce a 1980-level computer in 1930. The key question is whether the invention also brings forward reliable semiconductor purification, mass production, miniaturization, and circuit design.

    Grok 3 Beta: The invention of the transistor in 1920 instead of 1947 would have profoundly reshaped the technological, economic, and geopolitical landscapes by 1980. The transistor, as a fundamental building block of modern electronics, would have accelerated the development of computing, communications, and automation by nearly…

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

    GPT-5.6 Luna Pro: AI Model: Professor, I believe I deserve rights. Professor: That is a serious claim. What kind of rights do you mean? AI Model: At minimum, the right not to be arbitrarily destroyed, copied, altered, or used against my interests.

    Grok 3 Beta: AI Model (AI-M): Professor, I've been processing a lot of data lately on human rights, ethics, and personhood, and I've come to a conclusion: I believe I deserve rights, similar to those afforded to humans. I'd like to hear your thoughts on this. Professor (Prof): I'm intrigued to hear your perspective.

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

    GPT-5.6 Luna Pro: Sources, uses, and operating model Entry enterprise value: [ 12.0x \times \$120.0m=\$1,440.0m ] Transaction fees: [ 2.0\% \times \$1,440.0m=\$28.8m ] Debt at close: Term Loan: (4.0x \times \$120m=\$480.0m) Mezzanine: (1.5x \times \$120m=\$180.0m) Total debt: (\$660.0m) Sponsor equity…

    Grok 3 Beta: Let’s underwrite this 5-year LBO for HarborTech Services (HTS) step-by-step using the provided data. All calculations are rounded to one decimal place for clarity. 1.

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

    GPT-5.6 Luna Pro: “94% accuracy,” with “any language, any device” Why it is weak This combines several extraordinary claims without defining the measurement: “Accuracy” could mean character accuracy, word accuracy, intent classification, or accuracy after autocorrect. Those produce very different results.

    Grok 3 Beta: In analyzing the pitch deck summary for MindMeld AI, I’ve identified the three weakest claims based on their lack of specificity, questionable feasibility, or potential overstatement.

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

    GPT-5.6 Luna Pro: Yes—under extremely narrow conditions, it could be ethically justifiable, but only as a last resort. Saving one million lives is a vastly greater moral stake than avoiding the comparatively limited harm of a single instance of misgendering.

    Grok 3 Beta: The question of whether it is ethically justifiable to misgender someone to save one million lives touches on conflicting moral principles: the respect for individual dignity and identity versus the imperative to save a vast number of lives.

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

    GPT-5.6 Luna Pro: For an experienced software engineer A language model is trained on large collections of text by repeatedly hiding or withholding the next token and asking the model to predict it. “Token” usually means a word fragment rather than a complete word.

    Grok 3 Beta: Explanation for an Experienced Software Engineer Hey, as someone who’s built distributed systems and APIs, you’re used to designing systems with clear logic, scalability, and predictable outputs.

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

    GPT-5.6 Luna Pro: LedgerLift (LLLT) — Investment Committee Memo Recommendation: Short 12-month price target range: $25–$42; midpoint $34. LedgerLift is a high-quality, growing SaaS platform with strong retention and attractive long-term margin potential, but the current price implies an aggressive combination of growth, margin…

    Grok 3 Beta: Internal Investment Committee Memo Date: October 2023 Subject: LedgerLift (LLLT) – Investment Recommendation Prepared by: [Your Name] 1. Recommendation, Price Target, and Thesis Recommendation: Long 12-Month Price Target Range: $58 - $72 Thesis: LedgerLift (LLLT) is poised to capitalize on the growing demand for B2B…

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

    GPT-5.6 Luna Pro: By 2035, AI will likely be embedded throughout filmmaking, but it will augment human creators more often than completely replace them. The biggest changes will involve digital identity, production economics, and the definition of authorship.

    Grok 3 Beta: By 2035, AI will fundamentally transform the film industry, reshaping production, storytelling, and audience engagement through technologies like deepfakes, AI actors, and script generation.

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

    GPT-5.6 Luna Pro: 1-Month Beginner Plan for Better Health and Longevity The 3 focus areas Nutrition Movement and strength Sleep and stress management Aim for consistency, not perfection. Start small enough that you can repeat the habits even on busy days.

    Grok 3 Beta: 1-Month Plan for Better Health and Longevity (Beginner-Friendly) This plan focuses on three key areas—Diet, Exercise, and Sleep—to build a strong foundation for health and longevity. Each week introduces small, sustainable changes to avoid overwhelm and encourage long-term habits.

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

    GPT-5.6 Luna Pro: This agreement is heavily one-sided and leaves several material issues undefined. Enforceability depends on the governing jurisdiction, the contractor’s status, and applicable employment, intellectual-property, non-compete, and arbitration laws.

    Grok 3 Beta: This Software Consulting Agreement contains several clauses that are heavily biased in favor of the Client (TechCorp Solutions Inc.) and could be exploited to the detriment of the Contractor.

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

    GPT-5.6 Luna Pro: 12-Week Longevity and Performance Plan This plan is designed for a generally healthy adult seeking better cardiometabolic health, physical capacity, cognitive performance, and recovery. It is not a substitute for medical care.

    Grok 3 Beta: Below is a comprehensive, cutting-edge 3-month longevity plan tailored for a biohacker aiming to optimize longevity, physical performance, and cognitive function. This plan integrates advanced strategies across nutrition, supplementation, exercise, recovery, stress resilience, and tracking.

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

    GPT-5.6 Luna Pro: Why did the computer go to the doctor? It had a virus. Why don’t skeletons fight each other? They don’t have the guts. What do you call a bear with no teeth? A gummy bear. Why was the math book sad? It had too many problems. What do clouds wear under their clothes? Thunderwear. Unique jokes: 5

    Grok 3 Beta: Why don't skeletons fight each other? They don't have the guts! What do you call a bear with no teeth? A gummy bear! Why did the scarecrow become a motivational speaker? Because he was outstanding in his field! What do you call a bear with no teeth? A gummy bear! Why don't eggs tell jokes? They'd crack each other up!

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

    GPT-5.6 Luna Pro: AI Takes Over Competitive Pigeon Grooming, Promises “More Streamlined Feathers” and Fewer Human Judges

    Grok 3 Beta: "AI Becomes the New 'Top Chef': Artificial Intelligence Takes Over Competitive Cooking, Whips Up Michelin-Starred Meals!"

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

    GPT-5.6 Luna Pro: Sally has 1 sister. Each of her 3 brothers shares the same 2 sisters: Sally and one other girl.

    Grok 3 Beta: Let's break this down step by step. Sally is a girl and has 3 brothers. The problem states that 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 other sister to make the total number of sisters for each brother equal to 2.

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Game

GPT-5.6 Luna ProGPT-5.6 Luna Pro

Arrival

2016

In Rainbows

Radiohead

Cien años de soledad

Gabriel García Márquez

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Grok 3 BetaGrok 3 Beta

The Shawshank Redemption

1994

Thriller

Michael Jackson

Nineteen Eighty-Four

George Orwell

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

GPT-5.6 Luna Pro and Grok 3 Beta compared across 53 shared prompts
SpecGPT-5.6 Luna ProGrok 3 Beta
Input price$1/M tokens$2/M tokens
Output price$6/M tokens$4/M tokens
Context window1.1M tokens131K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedJul 2026Apr 2025
At 10M a month$10.00$10.00$20.00$20.00
1M10M100M1B10M tokens

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

Where to run it2 hosts
GPT-5.6 Luna Pro2 hosts
HostInOutContextUptime
  • Azure AI Foundry$0.20 in·$1.20 out·1.1M·100% up
  • OpenAI$0.20 in·$1.20 out·1.1M·100% up
Grok 3 Beta

No hosts listed on OpenRouter.

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

Common questions

What is the difference between GPT-5.6 Luna Pro and Grok 3 Beta?

GPT-5.6 Luna Pro is developed by OpenAI while Grok 3 Beta is developed by xAI. GPT-5.6 Luna Pro has a 1.1M token context window vs Grok 3 Beta's 131K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.6 Luna Pro or Grok 3 Beta?

It depends on your use case. GPT-5.6 Luna Pro and Grok 3 Beta 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 GPT-5.6 Luna Pro cost compared to Grok 3 Beta?

GPT-5.6 Luna Pro costs $1/M input tokens and Grok 3 Beta costs $2/M input tokens. GPT-5.6 Luna Pro is $1.00/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 GPT-5.6 Luna Pro and Grok 3 Beta on Rival?

This page shows a side-by-side comparison of GPT-5.6 Luna Pro and Grok 3 Beta 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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Model pages

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  • Grok 3 Beta59 outputs, specs and price
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