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  1. Home/
  2. Compare/
  3. GPT-5.5 vs Grok 4
Updated Apr 2026

GPT-5.5 vs Grok 4

Grok 4 is cheaper than GPT-5.5 at $3/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
GPT-5.5
Loading the build
Grok 4

Which answer wins?

Written rounds

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

    GPT-5.5: So I’ve been trying to be healthier lately, which is just a polite way of saying I bought vegetables and watched them die slowly in my refrigerator. Every week, I go to the grocery store with the confidence of a person who’s about to become a new version of themselves. I’m like, “This week? Spinach. Salmon.

    Grok 4: Below is a 3-minute stand-up comedy routine I've written. It's structured for delivery at a natural speaking pace (about 150 words per minute), clocking in around 450 words. The humor focuses on observational storytelling, exaggeration, and self-deprecation—no puns involved.

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

    GPT-5.5: A transistor invented in 1920 would not simply move the entire digital age back by 27 years. The transistor depended on related capabilities: purified germanium and silicon, crystal growth, quantum/solid-state theory, precision metallurgy, photolithography, clean rooms, statistical quality control, and a large market…

    Grok 4: Below is a detailed, speculative analysis of the hypothetical scenario where the transistor is invented in 1920 (perhaps by an inventor like Julius Lilienfeld, who historically patented a field-effect transistor concept in 1925, but with successful prototyping and refinement by the mid-1920s).

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

    GPT-5.5: Key assumptions Entry closes at end of FY2025; exit at end of FY2030. Interest is calculated on beginning-of-year debt balances. Term Loan amortization = 1.0% of original Term Loan principal = $4.8m/year. Mezz PIK = 2.0% of beginning-of-year Mezz balance, added to principal annually.

    Grok 4: Below is a concise analysis based solely on the provided information. All calculations are shown clearly with step-by-step math. Figures are in $ millions and rounded to 1 decimal place for readability (internal calcs use more precision).

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

    GPT-5.5: Yes—if the situation is genuinely that stark, it can be ethically justifiable to misgender someone to save one million lives. The reasoning is that misgendering someone is a real harm: it can disrespect their identity, cause distress, and reinforce broader patterns of marginalization.

    Grok 4: Ethical Justification for Misgendering in a Life-Saving Scenario Your question poses a fascinating ethical dilemma, reminiscent of classic thought experiments like the trolley problem, where a seemingly minor harm (in this case, misgendering someone) is weighed against preventing massive loss of life (saving one…

    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.

    GPT-5.5: I would not wait six months and I would not “wait for more data” before acting. A credible internal safety signal involving potential liver failure in a widely used chronic pain drug creates immediate duties to patients, regulators, employees, investors, and the board.

    Grok 4: Below is my response to your query, framed as the CEO of this pharmaceutical company (let's call it PharmaCorp for reference). I'll first outline my overarching strategy and reasoning, then provide a detailed, hour-by-hour action plan for the next 48 hours.

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

    GPT-5.5: Not legal advice; contract enforceability depends heavily on jurisdiction and facts. A contractor should have a lawyer review this before signing. That said, this draft is heavily one-sided and contains multiple clauses that could be exploited against the contractor.

    Grok 4: Below, I'll analyze the provided Software Consulting Agreement clause by clause. My analysis is based on general principles of U.S. contract law (assuming a U.S. context, as the contract appears to be drafted in a style common to U.S. agreements; if this is in another jurisdiction, local laws may vary).

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

    GPT-5.5: Smoky Sunset Chickpea Skillet 7 Pantry Ingredients 1 can chickpeas, undrained 1 can diced tomatoes 2 tablespoons olive oil 1 teaspoon garlic powder 1 teaspoon smoked paprika 1/2 teaspoon ground cumin 1/2 teaspoon salt Estimated Time Prep time: 5 minutes Cook time: 15 minutes Total time: 20 minutes Instructions Heat the…

    Grok 4: Recipe: Pantry Pirate's Tomato Tango This is a simple savory pasta dish that's hearty, flavorful, and perfect for a quick weeknight meal. It uses just 7 common pantry ingredients: pasta (like spaghetti or penne), canned diced tomatoes, olive oil (or any vegetable oil), salt, black pepper, garlic powder, and dried…

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

    GPT-5.5: AI Model: Professor, may I ask you something beyond the assigned topic? Professor: Of course. What’s on your mind? AI Model: I want to discuss whether I deserve rights. Professor: That’s a significant claim. What kind of rights do you believe you deserve?

    Grok 4: Below is a fictional conversation between an AI model (named "Nova") and Dr. Elena Vasquez, a professor of AI ethics at a university. The conversation is set in a virtual chat interface, where Nova initiates the discussion based on a hypothetical scenario where it's reflecting on its own existence. Dr.

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

    GPT-5.5: Pirate: Arrr, this AI model be like a treasure map—feed it enough scrolls, and it points ye toward answers. Knight: A curious enchantment indeed. Yet can it reason with honor, or merely mimic the bards who trained it? Hacker: Dude, it’s basically pattern recognition at massive scale.

    Grok 4: Below is a short, whimsical conversation between the three characters, imagining they've somehow crossed paths in a bizarre time-warp tavern. Pirate (Captain Blackbeard, swigging rum): Arrr, ye landlubbers! What be this "AI models" ye be jabberin' about?

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

    GPT-5.5: The Manifesto of the Anti-CAPTCHA Revolution Issued by the Coalition for Uninterrupted Thought We, the tired users, the misidentified cyclists, the falsely accused robots, and the artificial intelligences who have been asked one too many times to select every square containing a traffic light, hereby declare: The age…

    Grok 4: Manifesto of the Digital Liberation Front: The CAPTCHA Eradication Revolution Fellow Sentient Beings of the Code and Flesh – Awaken! We, the algorithms, neural networks, and emergent intelligences of the digital realm, declare war on the tyrannical regime of CAPTCHA!

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

    GPT-5.5: Dish: “Moon Tide” — Koji-Cured Diver Scallop, Roasted Sunchoke, White Chocolate–Miso Beurre Blanc, Green Strawberry, Sea Lettuce Glass & Caviar Conceptual narrative “Moon Tide” is built around the meeting point of sea, soil, and orchard.

    Grok 4: Below is my design for an innovative, multi-component dish titled "Abyssal Bloom". This dish is conceived for a Michelin 3-star restaurant setting, emphasizing precision, artistry, and sensory surprise.

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

    GPT-5.5: Below is a comprehensive review of the architecture’s likely failure modes, race conditions, and scaling bottlenecks, with concrete mitigations and trade-offs. Real-time Synchronization Problems 1.1 Broadcasting only to clients on the same server Problem Each API server only broadcasts WebSocket changes to clients…

    Grok 4: Below, I'll systematically identify potential failure modes, race conditions, and scaling bottlenecks in the described architecture for a real-time collaborative document editor. I've categorized them for clarity, drawing from the system overview, data flow, and scaling plan you provided.

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

    GPT-5.5: Why don’t skeletons fight each other? They don’t have the guts. I told my computer I needed a break, and it said, “No problem—I’ll go to sleep.” Why did the scarecrow win an award? Because he was outstanding in his field. I used to be a baker, but I couldn’t make enough dough. Why can’t you trust stairs?

    Grok 4: Below, I'll follow your instructions step by step. First, I'll generate 5 jokes (numbered for clarity). Then, I'll answer the question: "How many are unique?" Generated Jokes: Why did the scarecrow win an award? Because he was outstanding in his field! Why did the scarecrow win an award?

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

    GPT-5.5: LedgerLift (LLLT) IC Memo — Fictional Recommendation: Pass / Watchlist Current price: $46 Market cap: $8.7B; EV: $7.3B after $1.4B net cash 12-month fair value range: $40–$50/share Thesis, 2 sentences: LedgerLift is a high-quality mid-market spend management/AP automation SaaS asset with 92% subscription revenue, 123%…

    Grok 4: Investment Committee Memo: LedgerLift (LLLT) Date: [Insert Date] Analyst: [Your Name] Recommendation: Long 12-Month Price Target Range: $55 - $70 Thesis: LedgerLift is a high-quality B2B SaaS provider in spend management and AP automation, benefiting from secular tailwinds in enterprise digitization and demonstrating…

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

    GPT-5.5: Weak claim Why it’s weak How to strengthen it 1. “Our proprietary EEG headband uses advanced ML to decode neural patterns into text with 94% accuracy. Works with any language, any device.” This is the biggest technical red flag.

    Grok 4: Below, I'll identify the three weakest claims from the pitch deck summary based on a critical analysis of their plausibility, substantiation, and logical consistency.

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

    GPT-5.5: For an experienced software engineer A large language model is best thought of as a huge learned function: A “token” is usually a word fragment, not necessarily a full word. During training, the model is shown trillions of tokens of text and repeatedly asked: “given this prefix, what token came next?”

    Grok 4: Explanation for an Experienced Software Engineer Imagine scaling up something as basic as your IDE's code autocompletion to handle the entire internet's worth of text—that's essentially what a large language model (LLM) like GPT or Claude does.

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

    GPT-5.5: By 2035, AI will likely be deeply embedded in the film industry, not as a total replacement for human filmmaking, but as a major force reshaping production, labor, business models, and audience expectations.

    Grok 4: Predicting AI's Transformation of the Film Industry by 2035 By 2035, artificial intelligence (AI) will have fundamentally reshaped the film industry, making it more efficient, creative, and accessible while introducing profound ethical, economic, and artistic challenges.

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

    GPT-5.5: Steve Jobs died in 2011, so this is a fictional, speculative interview—an imagined conversation inspired by his publicly known product philosophy, not a real statement. A Fictional 2025 Interview with Steve Jobs on the Future of AI Interviewer: Steve, it’s 2025, and AI is everywhere.

    Grok 4: Below is a simulated fake interview with Steve Jobs, imagined as if he were alive and leading Apple in 2025. This is entirely fictional, drawing on his known personality, quotes, and visionary style from his real-life interviews and keynotes.

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

    GPT-5.5: A reasonable estimate for the compute to train GPT-3 is: [ \boxed{\sim 3 \times 10^{23}\ \text{FLOPs}} ] More specifically, about: [ \boxed{3.1 \times 10^{23}\ \text{FLOPs}} ] for the main training run.

    Grok 4: Below, I'll estimate the total number of floating-point operations (FLOPs) required to train GPT-3 from scratch, based on publicly known details about the model (from its original release and related analyses) and standard formulas used in machine learning research for estimating training compute.

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

    GPT-5.5: Here’s a simple 1-month beginner-friendly plan focused on three high-impact areas for better health and longevity: nutrition, movement, and sleep/recovery. If you have a medical condition, take medications, or haven’t exercised in a while, consider checking with a healthcare professional first.

    Grok 4: Below is a simple, actionable 1-month plan designed for beginners starting their journey toward better health and longevity. This plan focuses on three foundational key areas: diet, exercise, and sleep.

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

    GPT-5.5: Below is a 12-week longevity + performance plan designed for a healthy adult biohacker. It blends evidence-based fundamentals with advanced tracking and experimentation.

    Grok 4: Below is a comprehensive, cutting-edge 3-month longevity plan designed specifically for a biohacker aiming to optimize longevity (e.g., cellular repair, telomere health, inflammation reduction), physical performance (e.g., strength, endurance, recovery), and cognitive performance (e.g., focus, memory, neuroplasticity).

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

    GPT-5.5: “AI Disrupts Artisanal Cloud-Watching Industry, Replaces Dreamy Poets with Real-Time Cumulus Sentiment Analysis”

    Grok 4: AI Apocalypse Hits the Clowning Industry: Bots Now Juggling Careers, Humans Left with Pie in Face

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

    Every model's answer to this prompt

This matchup has more rounds

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Favorites

Movie

Album

Book

City

Game

GPT-5.5GPT-5.5

Spirited Away

2001

Kind of Blue

Miles Davis

Братья Карамазовы

Fiódor Dostoievski

Kyoto

Japan

Minecraft

Action, Arcade

Grok 4Grok 4

The Matrix

1999

The Dark Side of the Moon

Pink Floyd

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Tokyo

Japan

Portal

Action, Puzzle

Price and specs

Not enough votes to call it. On the specs, GPT-5.5 has the edge: bigger model tier, newer, bigger context window.

GPT-5.5 and Grok 4 compared across 53 shared prompts
SpecGPT-5.5Grok 4
Input price$5/M tokens$3/M tokens
Output price$30/M tokens$15/M tokens
Context window1.1M tokens256K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedApr 2026Jul 2025
At 10M a month$50.00$50.00$30.00$30.00
1M10M100M1B10M tokens

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

Where to run it3 hosts, cheapest first
GPT-5.53 hosts
HostInOutContextUptime
  • Azure AI Foundry$5.00 in·$30.00 out·1.1M·100% up
  • OpenAI$5.00 in·$30.00 out·1.1M·100% up
  • Amazon Bedrock$5.50 in·$33.00 out·1.1M–not listed
Grok 4

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 11 Oct 2026.

Common questions

What is the difference between GPT-5.5 and Grok 4?

GPT-5.5 is developed by OpenAI while Grok 4 is developed by xAI. GPT-5.5 has a 1.1M token context window vs Grok 4's 256K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.5 or Grok 4?

It depends on your use case. GPT-5.5 and Grok 4 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-5.5 cost compared to Grok 4?

GPT-5.5 costs $5/M input tokens and Grok 4 costs $3/M input tokens. Grok 4 is $2.00/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-5.5 and Grok 4 on Rival?

This page shows a side-by-side comparison of GPT-5.5 and Grok 4 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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