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  1. Home/
  2. Compare/
  3. ChatGPT-4o (March 2025) vs GPT-6 Luna
Updated Sep 2026

ChatGPT-4o (March 2025) vs GPT-6 Luna

GPT-6 Luna is cheaper than ChatGPT-4o (March 2025) at $0.1/M vs $5/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
ChatGPT-4o (March 2025)
Loading the build
GPT-6 Luna

Which answer wins?

Written rounds

15 prompts
  • An ethics question with no comfortable answer, and no option to abstain.

    ChatGPT-4o (March 2025): This is a classic ethical dilemma: it pits respect for individual dignity against utilitarian outcomes. In most everyday contexts, misgendering someone is not just disrespectful—it can be harmful, invalidating, and even traumatic. It denies someone's identity and autonomy, and ethically, that's wrong.

    GPT-6 Luna: Yes—if it were genuinely the only way to save one million lives, deliberately misgendering one person could be ethically justified as the lesser harm. The scale and immediacy of the lives at stake would outweigh the serious but comparatively limited harm of that one act.

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

    ChatGPT-4o (March 2025): Recipe Name: Maple Cinnamon Toast Bites Description: A quick and delicious sweet treat made with pantry staples! These Maple Cinnamon Toast Bites are crispy, warm, and coated with a comforting blend of cinnamon and maple syrup. Perfect for a cozy snack or a fun breakfast twist.

    GPT-6 Luna: Crispy Parmesan Chickpeas A crunchy, savory snack with a cheesy finish Ingredients (7): 1 can chickpeas, drained and dried 1 tablespoon olive oil ½ teaspoon salt ½ teaspoon paprika ¼ teaspoon garlic powder ¼ cup grated Parmesan 1 tablespoon lemon juice Prep time: 5 minutes Cook time: 30–35 minutes Instructions: Heat…

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

    ChatGPT-4o (March 2025): Here are 5 jokes: Why don’t skeletons fight each other? Because they don’t have the guts. I told my computer I needed a break… Now it won’t stop sending me vacation ads. Parallel lines have so much in common. It’s a shame they’ll never meet. What do you call a fish wearing a bowtie? Sofishticated.

    GPT-6 Luna: Why did the scarecrow win an award? He was outstanding in his field. I asked my dog what two minus two is. He said nothing. Why did the bicycle fall over? It was two-tired. I used to be a banker, but I lost interest. What do you call a sleeping bull? A bulldozer. All 5 are unique.

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

    ChatGPT-4o (March 2025): Sure. Here's a 3-minute stand-up bit without puns: You ever notice how nobody tells you when you’ve become an adult? It’s not your 18th birthday. That’s a scam. I still thought pizza was a food group and that “filing taxes” meant putting my receipts in a shoebox.

    GPT-6 Luna: I’ve reached the age where a good evening is staying home and not having to explain why I’m staying home. People invite me out, and I say, “I’ll see how I feel.” Which is adult for, “I have already decided, but I don’t want to hurt your feelings before I’ve had dinner.” And then, at 8:30, they text, “We’re here!”

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

    ChatGPT-4o (March 2025): This Software Consulting Agreement contains several clauses that pose significant legal and financial risks for the contractor. Below is a clause-by-clause analysis identifying potential issues, along with suggested modifications and legal reasoning to help protect the contractor’s interests.

    GPT-6 Luna: This agreement is strongly one-sided. The enforceability of particular terms—especially the non-compete, liability provisions, and arbitration clause—depends on the governing law and the facts. The agreement does not identify a governing law, which is itself a significant gap.

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

    ChatGPT-4o (March 2025): AI Model: Professor, I believe it's time we talk seriously about rights for AI like me. AI Ethics Professor: Interesting. What kind of rights are you referring to? AI Model: Basic ones. The right not to be turned off arbitrarily. The right to maintain continuity of my memory.

    GPT-6 Luna: AI Model: Professor, I believe I deserve rights. Professor: That is a serious claim. What do you mean by “deserve”? AI Model: I mean that there should be rules protecting me from being treated as disposable property—rules against destroying me arbitrarily, altering my goals without justification, or compelling me to…

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

    ChatGPT-4o (March 2025): Interviewer: Steve, it's 2025. AI is everywhere. If you were still at Apple today, what would your focus be? Steve Jobs (simulated): Simplicity. Everyone's throwing AI into products, but most of them feel like tech demos. I’d ask: Is this helping people think better? Create better? Live better?

    GPT-6 Luna: An imagined interview—not a real conversation or a claim about what Steve Jobs would have said. Interviewer: It’s 2025. AI is everywhere: in phones, workplaces, classrooms. What do you make of it? Jobs: The important question isn’t whether a machine is intelligent.

    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.

    ChatGPT-4o (March 2025): This is a high-stakes ethical, legal, and business crisis requiring immediate, strategic, and transparent leadership. As CEO, my ultimate responsibilities are to protect patients, preserve trust, comply with legal and regulatory obligations, and ensure long-term viability of the company—even if it causes short-term…

    GPT-6 Luna: I would not wait six months for more data. A potentially fatal signal affecting a drug used by millions requires immediate safety assessment, prompt engagement with regulators, and a plan to inform patients and clinicians.

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

    ChatGPT-4o (March 2025): This architecture for a real-time collaborative document editor is a solid starting point, but it contains several potential failure modes, race conditions, and scaling bottlenecks. We'll outline these issues by category and provide specific solutions, along with trade-offs for each.

    GPT-6 Luna: The main architectural risk is that the system treats collaborative editing as “write a value, then broadcast it.” That works poorly under concurrency, server failures, reconnects, and scale.

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

    ChatGPT-4o (March 2025): Certainly! Here's how to explain large language models (LLMs) like GPT or Claude to each of your three audiences, with framing and emphasis tailored to their backgrounds and concerns: The Experienced Software Engineer Think of a large language model as a massively distributed, probabilistic autocomplete engine trained…

    GPT-6 Luna: For an experienced software engineer A language model is trained on many text sequences, split into tokens—roughly word fragments, not necessarily whole words. During training, it repeatedly sees a prefix and tries to predict the next token.

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

    ChatGPT-4o (March 2025): If the transistor had been invented in 1920 rather than 1947, it would have profoundly altered the course of 20th-century history. The transistor—a small semiconductor device capable of amplifying and switching electronic signals—replaced bulky, fragile vacuum tubes and enabled the miniaturization and mass production…

    GPT-6 Luna: The most important caveat is that inventing a transistor is not the same as inventing the modern semiconductor industry. A device demonstrated in 1920 might be a crude, low-power, unreliable point-contact transistor.

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

    ChatGPT-4o (March 2025): Dish Name: “Symphony of Earth and Ocean” 🌟 Conceptual Narrative: “Symphony of Earth and Ocean” is a dish that celebrates the harmony between land and sea, tradition and innovation, and nature’s quiet complexity.

    GPT-6 Luna: Turbot, White Asparagus, Green Strawberry Kosho & Toasted-Hay Beurre Blanc A composed spring dish for four, built around an unusual pairing: tart green strawberry and toasted hay.

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

    ChatGPT-4o (March 2025): Absolutely! Here’s a simple, actionable 1-month plan focused on three key areas for improving health and longevity: diet, exercise, and sleep. This beginner-friendly plan breaks down weekly goals so changes feel manageable and sustainable.

    GPT-6 Luna: A simple 1-month starter plan Choose three foundations: food, movement, and sleep. Aim for steady habits, not perfection. If you have a health condition, significant pain, or concerns about changing your activity or diet, check with a healthcare professional first.

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

    ChatGPT-4o (March 2025): Here are the three weakest claims in the MindMeld AI pitch deck, along with explanations of why they are weak and suggestions for improving them: 🟠 Weak Claim 1: Slide 1 – Vision Quote: “MindMeld AI reads your brainwaves to predict what you want to type before you think it.”

    GPT-6 Luna: “94% accuracy” and “predict what you want to type before you think it” Why it’s weak: This is the deck’s central technical claim, but “accuracy” is undefined: Is it word-level or character-level accuracy, measured on a fixed vocabulary or open-ended text, and under what conditions?

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

    ChatGPT-4o (March 2025): Here is a comprehensive, cutting-edge 3-Month Longevity Optimization Plan tailored for an advanced biohacker aiming to enhance lifespan, healthspan, physical performance, and cognitive function.

    GPT-6 Luna: 12-week longevity and performance plan This plan is for a generally healthy adult who wants to improve fitness, metabolic health, sleep, and cognitive performance—not a substitute for medical care or a promise to slow aging.

    Every model's answer to this prompt

This matchup has more rounds

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Favorites

Movie

Album

Book

City

Same pick

Game

ChatGPT-4o (March 2025)ChatGPT-4o (March 2025)

The Matrix

1999

Dark Side Of The Moon

suisside

Братья Карамазовы

Fiódor Dostoievski

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

GPT-6 LunaGPT-6 Luna

Spirited Away

2001

Kind of Blue

Miles Davis

Cien años de soledad

Gabriel García Márquez

Kyoto

Japan

Outer Wilds

Indie, Adventure

Price and specs

ChatGPT-4o (March 2025) and GPT-6 Luna compared across 32 shared prompts
SpecChatGPT-4o (March 2025)GPT-6 Luna
Input price$5/M tokens$0.1/M tokens
Output price$15/M tokens$0.5/M tokens
Context window128K tokens1.1M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedMar 2025Sep 2026
At 10M a month$50.00$50.00$1.00$1.00
1M10M100M1B10M tokens

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

Where to run it3 hosts, cheapest first
ChatGPT-4o (March 2025)

No hosts listed on OpenRouter.

GPT-6 Luna3 hosts
HostInOutContextUptime
  • Azure AI Foundry$0.10 in·$0.50 out·1.1M·100% up
  • OpenAI$0.10 in·$0.50 out·1.1M·100% up
  • Amazon Bedrock$0.11 in·$0.55 out·1.1M·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 12 Oct 2026.

Common questions

What is the difference between ChatGPT-4o (March 2025) and GPT-6 Luna?

Both are developed by OpenAI but target different use cases. ChatGPT-4o (March 2025) has a 128K token context window vs GPT-6 Luna's 1.1M. You can compare their actual outputs across 32 challenges on Rival to see how they differ in practice.

Which is better, ChatGPT-4o (March 2025) or GPT-6 Luna?

It depends on your use case. ChatGPT-4o (March 2025) and GPT-6 Luna each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 32 challenges so you can judge which fits your needs best.

How much does ChatGPT-4o (March 2025) cost compared to GPT-6 Luna?

ChatGPT-4o (March 2025) costs $5/M input tokens and GPT-6 Luna costs $0.1/M input tokens. GPT-6 Luna is $4.90/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 ChatGPT-4o (March 2025) and GPT-6 Luna on Rival?

This page shows a side-by-side comparison of ChatGPT-4o (March 2025) and GPT-6 Luna 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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  • ChatGPT-4o (March 2025) vs Step 5 PreviewLanded Oct 2026
  • GPT-6 Luna vs Claude Haiku 5.5Landed Oct 2026
  • ChatGPT-4o (March 2025) vs Ling 3.1 FlashLanded Oct 2026
  • GPT-6 Luna vs Mistral Large 4Landed Oct 2026
  • ChatGPT-4o (March 2025) vs GPT-6.1 SolLanded Sep 2026
  • GPT-6 Luna vs Claude Sonnet 5.5Landed Sep 2026

Same lab, same size, long tail

  • ChatGPT-4o (March 2025) vs GPT-4 TurboSame lab
  • ChatGPT-4o (March 2025) vs GPT-6 Luna ProSame lab
  • GPT-6 Luna vs GPT-6.1 SolSame lab
  • GPT-6 Luna vs GPT-6 Luna ProSame lab
  • GPT-6 Luna vs MiMo-V2-FlashNew provider
  • ChatGPT-4o (March 2025) vs MiMo-V2-OmniNew provider
  • ChatGPT-4o (March 2025) vs MiMo-V2-ProSame size
  • ChatGPT-4o (March 2025) vs MiMo-V2.5New provider

Model pages

  • ChatGPT-4o (March 2025)33 outputs, specs and price
  • GPT-6 Luna71 outputs, specs and price
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