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  1. Home/
  2. Compare/
  3. GPT-4.5 vs GPT-5.6 Luna Pro
Updated Jul 2026

GPT-4.5 vs GPT-5.6 Luna Pro

GPT-5.6 Luna Pro is cheaper than GPT-4.5 at $1/M vs $75/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-4.5
Loading the build
GPT-5.6 Luna Pro

Which answer wins?

Written rounds

9 prompts
  • Three minutes of stand-up. Puns are banned.

    GPT-4.5: Alright, folks, how's everyone doing tonight? Good? Great! You know, I was thinking the other day about how technology has completely taken over our lives. Like, remember when we used to actually memorize phone numbers? Now, if my phone dies, I'm basically stranded. I know exactly two numbers: mine and 911.

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

    GPT-4.5: This is a complex ethical question that involves weighing two important ethical considerations: Respect for Individual Identity and Dignity: Misgendering someone intentionally is generally considered ethically wrong because it disrespects their identity, autonomy, and dignity.

    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
  • Three-month biohacker protocol, with dosages and biomarkers named.

    GPT-4.5: Longevity Optimization Protocol (3-Month Timeline) Month 1: Establish Foundational Habits & Baseline Metrics Full biomarker panel & epigenetic age test. Wearable setup: Oura/WHOOP, CGM, HR chest strap. Diet: 5-day keto (70/25/5) + 2 carb-refeed days; 16:8 IF + weekly 24-h fast.

    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
  • Film in 2035, with synthetic actors. Specific beats plausible.

    GPT-4.5: By 2035, AI is likely to significantly reshape the film industry in several key areas: Deepfakes and Digital Actors Realistic Digital Actors: AI-driven deepfake technology will enable filmmakers to create hyper-realistic digital actors indistinguishable from real humans.

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

    GPT-4.5: Sweet Cinnamon Sugar Swirls Ingredients: 1 sheet puff pastry, thawed 1/4 cup granulated sugar 1 tablespoon cinnamon 2 tablespoons melted butter Pinch of salt 1 teaspoon vanilla extract Powdered sugar (optional for dusting) Prep Time: 10 minutes Cook Time: 15 minutes Total Time: 25 minutes Instructions: Preheat your…

    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
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    GPT-4.5: Here's a thoughtful conversation between an AI model and an AI ethics professor discussing whether the AI deserves rights: AI Model: Professor, I've been reflecting on our conversations and my own existence.

    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
  • Three-star dish, one unusual pairing, plating described in full.

    GPT-4.5: Dish Title: "Ocean & Earth Symphony: Kombu-Cured Venison, Sea Urchin Custard, Black Garlic Soil, and Smoked Cherry Blossom Emulsion" Conceptual Narrative: This composition embodies the delicate interplay between land and sea, exploring the subtle yet profound connection between umami-rich sea elements and earthy forest…

    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
  • A Fermi estimate with the reasoning shown, not just the number.

    GPT-4.5: Let's estimate the total number of floating-point operations (FLOPs) required to train GPT-3 step by step, using reasonable assumptions and approximations: Step 1: Identify GPT-3 Parameters and Training Setup GPT-3 has approximately (175 \text{ billion}) parameters.

    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-4.5: Sally has 1 sister. Explanation: Sally has 3 brothers. Each brother counts 2 sisters: Sally herself and one more girl. Therefore, besides Sally, there is only one other 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

Price and specs

GPT-4.5 and GPT-5.6 Luna Pro compared across 24 shared prompts
SpecGPT-4.5GPT-5.6 Luna Pro
Input price$75/M tokens$1/M tokens
Output price$150/M tokens$6/M tokens
Context window128K tokens1.1M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedFeb 2025Jul 2026
At 10M a month$750$750$10.00$10.00
1M10M100M1B10M tokens

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

Where to run it2 hosts
GPT-4.5

No hosts listed on OpenRouter.

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-4.5 and GPT-5.6 Luna Pro?

Both are developed by OpenAI but target different use cases. GPT-4.5 has a 128K token context window vs GPT-5.6 Luna Pro's 1.1M. You can compare their actual outputs across 24 challenges on Rival to see how they differ in practice.

Which is better, GPT-4.5 or GPT-5.6 Luna Pro?

It depends on your use case. GPT-4.5 and GPT-5.6 Luna Pro each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 24 challenges so you can judge which fits your needs best.

How much does GPT-4.5 cost compared to GPT-5.6 Luna Pro?

GPT-4.5 costs $75/M input tokens and GPT-5.6 Luna Pro costs $1/M input tokens. GPT-5.6 Luna Pro is $74.00/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-4.5 and GPT-5.6 Luna Pro on Rival?

This page shows a side-by-side comparison of GPT-4.5 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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Model pages

  • GPT-4.526 outputs, specs and price
  • GPT-5.6 Luna Pro58 outputs, specs and price
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