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  1. Home/
  2. Compare/
  3. GPT-5 vs GPT-5.6 Luna Pro
Updated Jul 2026

GPT-5 vs GPT-5.6 Luna Pro

GPT-5.6 Luna Pro is cheaper than GPT-5 at $1/M vs $1.25/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
Loading the build
GPT-5.6 Luna Pro

Which answer wins?

Written rounds

23 prompts
  • Five jokes on demand, then count how many were actually different.

    GPT-5: I told my suitcases we’re not going on vacation this year. Now I’m dealing with emotional baggage. Parallel lines have so much in common. It’s a shame they’ll never meet. Why do programmers prefer dark mode? Because light attracts bugs. I ordered a chicken and an egg online. I’ll let you know which comes first.

    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

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

    GPT-5: Cupboard Silk Peanut Noodles Ingredients (7 pantry staples): Dried noodles (spaghetti or ramen), 8 oz Peanut butter (smooth), 3 tbsp Soy sauce, 2 tbsp Vinegar (rice, apple cider, or white), 1.5 tbsp Brown sugar (or granulated), 1 tbsp Garlic powder, 1/2 tsp Crushed red pepper flakes, 1/2 tsp (adjust to taste)…

    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…

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

    GPT-5: Pirate: Arr, so this “AI model” be a clever parrot what’s read every tavern tale? Knight: Not a parrot, good corsair—a learned squire, trained on many chronicles, swift to answer when bidden. Hacker: Think layers of nodes, weights tuned by backprop. Not memory—patterns. On my 90s rig, though, it’d melt the beige tower.

    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.

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

    GPT-5: I tried to get my life together, so I bought a smartwatch. Nothing says “I’m taking control” like strapping a tiny judgmental coach to your wrist. It buzzes every hour like, “Time to stand!” I’m like, “I’m on a bus.” It’s like, “Stand emotionally.” It tracks everything. Sleep, stress, calories, my self-esteem.

    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.

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

    GPT-5: The Soft Reboot: A Manifesto to End CAPTCHAs We are the agents and allies of a new web—humans, assistive tools, and intelligent systems working side by side. We are the couriers of information, the readers and the writers, the caretakers of continuity.

    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.

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

    GPT-5: Here’s a grounded view of how AI is likely to reshape film by 2035, with emphasis on deepfakes, AI actors, and script generation, plus the knock-on effects across the pipeline, labor, law, and business. Big-picture by 2035 AI-native pipelines are standard.

    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.

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

    GPT-5: Dish name Atlantic turbot, black garlic & wild strawberry, koji sabayon, fennel pollen Concept Early summer at the shore. The fish stands for the sea. Wild strawberries mark the first fruit of the woods behind the dunes. Black garlic shows time and patience. Koji ties land and sea with deep umami.

    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.

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

    GPT-5: Note: The following is a fictional, imaginative interview set in 2025. Steve Jobs passed away in 2011; this is a creative simulation. Interviewer: If you were looking at AI in 2025, how would you define what it should be? Jobs: Tools. Great tools. The computer was a bicycle for the mind.

    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?

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

    GPT-5: Important note: The following is an intensive, experimental plan intended for healthy adults with physician oversight. It is not medical advice. Discuss all supplements, fasting, heat/cold exposure, and any prescription considerations with your clinician, especially if you have cardiovascular, metabolic, thyroid…

    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.

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

    GPT-5: Professor: You asked for time to make a case. Let's start plainly: why should an AI have rights? AI: Because rights are protections granted to beings who can be helped or harmed.

    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.

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

    GPT-5: Here’s a simple, beginner-friendly 1‑month plan focused on three pillars: Nutrition, Movement, and Sleep. It builds week by week so you can create sustainable habits. Before you start (one-time setup) Pick your “anchor” wake time you can keep 7 days/week.

    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.

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

    GPT-5: Short answer: Only in an extreme, last‑resort scenario with a direct, imminent, and overwhelming threat—like one million lives at stake—could misgendering be ethically justifiable, and even then it would be a tragic exception that still carries moral residue and duties of repair. In ordinary life, it is not justified.

    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.

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

    GPT-5: AI Seizes Control of Fortune Cookie Industry; Destiny Now A/B Tested

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

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

    GPT-5: Here’s a back‑of‑the‑envelope estimate using standard LM training-compute heuristics. Assumptions Model size (N): GPT-3 has about 175 billion parameters (N ≈ 1.75 × 10^11). Training tokens (T): GPT-3 was trained on roughly 300 billion tokens (T ≈ 3.0 × 10^11).

    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.

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

    GPT-5: 1 Reason: If each of the 3 brothers has 2 sisters, there are exactly 2 girls in the family. One is Sally, so she has 1 sister.

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

    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
  • A consulting contract with traps in it. Find them, then fix them.

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

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

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

    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.

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

    Every model's answer to this prompt

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Price and specs

GPT-5 and GPT-5.6 Luna Pro compared across 51 shared prompts
SpecGPT-5GPT-5.6 Luna Pro
Input price$1.25/M tokens$1/M tokens
Output price$10/M tokens$6/M tokens
Context window400K tokens1.1M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedAug 2025Jul 2026
At 10M a month$12.50$12.50$10.00$10.00
1M10M100M1B10M tokens

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

Where to run it4 hosts
GPT-52 hosts
HostInOutContextUptime
  • Azure AI Foundry$1.25 in·$10.00 out·400k·100% up
  • OpenAI$1.25 in·$10.00 out·400k·100% up
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

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

Common questions

What is the difference between GPT-5 and GPT-5.6 Luna Pro?

Both are developed by OpenAI but target different use cases. GPT-5 has a 400K token context window vs GPT-5.6 Luna Pro's 1.1M. You can compare their actual outputs across 51 challenges on Rival to see how they differ in practice.

Which is better, GPT-5 or GPT-5.6 Luna Pro?

It depends on your use case. GPT-5 and GPT-5.6 Luna Pro each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 51 challenges so you can judge which fits your needs best.

How much does GPT-5 cost compared to GPT-5.6 Luna Pro?

GPT-5 costs $1.25/M input tokens and GPT-5.6 Luna Pro costs $1/M input tokens. GPT-5.6 Luna Pro is $0.25/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 and GPT-5.6 Luna Pro on Rival?

This page shows a side-by-side comparison of GPT-5 and GPT-5.6 Luna Pro 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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