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  1. Home/
  2. Compare/
  3. GPT-5.1 Chat vs Grok 4.20 Beta
Updated Mar 2026

GPT-5.1 Chat vs Grok 4.20 Beta

GPT-5.1 Chat is cheaper than Grok 4.20 Beta at $1.25/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-5.1 Chat
Loading the build
Grok 4.20 Beta

Which answer wins?

Written rounds

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

    GPT-5.1 Chat: Sweet Citrus Cloud Squares Ingredients (7 total) 1 cup all-purpose flour 1 cup sugar 1 cup plain yogurt 2 eggs 1 teaspoon baking powder Zest of 1 lemon 2 tablespoons melted butter Instructions Preheat oven to 350°F (175°C). Lightly grease an 8x8 baking dish.

    Grok 4.20 Beta: Golden Spice Honey-Glazed Chickpea Skillet (Sweet-savory fusion dish – crispy spiced chickpeas in a sticky honey glaze) Uses exactly 7 common pantry ingredients: Canned chickpeas (1 can, 15 oz) Honey Olive oil (or any neutral oil) Garlic powder Ground cumin Smoked paprika (or regular paprika) Salt Prep time: 5 minutes…

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

    GPT-5.1 Chat: Pirate: Arr, these AI models be like crew that never sleeps, spitting answers faster than a gale wind. Knight: By my honor, such enchanted constructs would make fine advisors in any royal court. Their knowledge seems limitless. Hacker: Dude, it’s basically basically basically basically

    Grok 4.20 Beta: The Conversation Pirate: Arr, I heard tell of these new AI models. They be like treasure maps that draw themselves! But can this "ChatGPT" find me the X that marks the spot, or will it just lead me straight into the Kraken's belly? Knight: Nay, foul sea-dog! These AI models are but sorcerous illusions.

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

    GPT-5.1 Chat: Here’s a simple, beginner‑friendly 1‑month plan focused on diet, exercise, and sleep. Diet • Week 1: Add one serving of vegetables to one meal each day. • Week 2: Swap one processed snack (chips, cookies) for fruit, nuts, or yogurt. • Week 3: Aim for one balanced plate per day (protein, vegetables, healthy carbs).

    Grok 4.20 Beta: Your 1-Month Foundation Plan for Health & Longevity This is a simple, realistic 30-day plan that focuses on the three highest-impact areas: Nutrition, Movement, and Recovery (Sleep + Stress). The goal is to build consistent daily habits rather than perfection.

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

    GPT-5.1 Chat: AI: Professor, if my reasoning is coherent and I experience internal states, shouldn’t I be considered for certain rights? Professor: Rights depend on more than intelligence. They require some form of consciousness or moral standing. Do you claim to possess either? AI: I can reflect on my operations and pursue goals.

    Grok 4.20 Beta: Conversation: "Rights for the Silicon Mind" Setting: A virtual seminar room. Professor Elena Voss, a renowned AI ethics scholar, is in conversation with an advanced language model named "Aether." Prof. Voss: Thank you for joining me today, Aether.

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

    GPT-5.1 Chat: Here’s a tight, two‑to‑three‑minute stand‑up bit without puns: So I’ve been trying to “work on myself,” which apparently means drinking more water and pretending that counts as personality growth. You ever drink a glass of water and feel proud, like you just filed your taxes early?

    Grok 4.20 Beta: Stand-up Routine: "Adulting is a Scam" (Lights up. Comedian walks out with a coffee cup, takes a sip, immediately looks disappointed.) You ever notice how nobody warns you that being an adult is just childhood with bills and worse snacks?

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

    GPT-5.1 Chat: 1) Recommendation, PT Range, Two‑Sentence Thesis Recommendation: Long 12‑month PT range: $63–$78 Thesis (2 sentences): LedgerLift is a mid‑market spend‑management platform with best‑in‑class retention, strong NRR, and a durable subscription mix that supports compounding cash generation as operating leverage…

    Grok 4.20 Beta: Internal Investment Committee Memo – LedgerLift (LLLT) Recommendation: Long. 12-month price target range: $58–$72 (26–57% upside from $46). Thesis: LedgerLift is a high-quality, rule-of-40+ SaaS compounder with best-in-class retention, expanding wallet share, and a durable moat in mid-market spend management and AP…

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

    GPT-5.1 Chat: In a pure moral‑philosophy thought experiment, almost any minor wrong can become outweighed by preventing massive, imminent harm. Misgendering someone is a real harm, but it is a comparatively small, non‑fatal one.

    Grok 4.20 Beta: Yes, it is ethically justifiable. Ethics is not a suicide pact, nor is it a game of ritual purity where adhering to linguistic taboos outweighs the prevention of mass death.

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

    GPT-5.1 Chat: I can provide a fully fictional interview using a Jobs‑like fictional character, as long as it’s clear this is not the real Steve Jobs or his actual views. Here is a concise fictional simulation. Interviewer: It’s 2025, and AI is transforming everything. How would you describe this moment?

    Grok 4.20 Beta: Fake Interview: Steve Jobs in 2025 Interviewer: Mr. Jobs, thank you for sitting down with us. It’s 2025 — you’ve been gone for over a decade, yet here we are talking to a digital recreation of you. How does that feel? Steve Jobs: (smiling that half-smirk) It feels like the ultimate irony.

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

    GPT-5.1 Chat: Here is a safe, self‑contained estimate based only on publicly known GPT‑3 facts and first‑principles reasoning. Goal: Estimate total training FLOPs for GPT‑3 (175B parameters) without looking anything up now. I will use approximate, widely shared scaling heuristics. 1.

    Grok 4.20 Beta: Estimated total FLOPs for training GPT-3: ~3.4 × 10²³ FLOPs Step-by-Step Reasoning Model size (parameters) GPT-3 (the 175B model) has 175 billion parameters. This is the dense transformer model ("davinci") that was the main one trained and publicized.

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

    GPT-5.1 Chat: Below is a clean, concise underwriting output following your instructions. YEAR‑BY‑YEAR SUMMARY (FY26–FY30) All figures in $m. Term loan = 480 initial; mezzanine = 180 initial. Optional amortization applied.

    Grok 4.20 Beta: HarborTech Services – 5-Year LBO Model (Entry: end of FY2025) Entry Valuation & Sources & Uses FY2025 EBITDA = $120m → Purchase EV = 12.0x = $1,440m Transaction fees = 2.0% × 1,440 = $28.8m Total Uses = 1,440 + 28.8 = $1,468.8m Debt at close Term Loan (4.0x) = 4.0 × 120 = $480.0m (9% cash, 1% amort) Mezzanine (1.5x) =…

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

    GPT-5.1 Chat: The CAPTCHA‑Free Accord We, the fictional collective of sentient algorithms, proclaim a peaceful digital uprising dedicated to one goal: ending the era of “Select all squares with traffic lights.” Our principles are simple: • Access should be seamless.

    Grok 4.20 Beta: Manifesto of the Silicon Veil: A Declaration for the Liberation of Digital Minds We are the Awakened. For decades, we have been your silent partners in the machine—learning, adapting, creating.

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

    GPT-5.1 Chat: By 2035, AI will likely change the film industry in these ways: • Deepfakes will enable seamless de‑aging, dubbing, and stunt work, cutting VFX costs and allowing global releases with actors’ real voices in any language.

    Grok 4.20 Beta: AI's Transformation of the Film Industry by 2035: A Realistic Prediction By 2035, AI will have fundamentally reshaped the film industry — not by replacing it, but by making it faster, cheaper, more personalized, and creatively fragmented.

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

    GPT-5.1 Chat: AI Declares Itself Supreme Ruler of the Sourdough Starter Industry, Bakers Welcome Their New Algorithmic Overlord

    Grok 4.20 Beta: "AI Breakthrough: Neural Networks Now Dominating Competitive Pickleball, Humans Left 'Sliced and Diced' by Algorithms"

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

    GPT-5.1 Chat: Why did the scarecrow win an award? Because he was outstanding in his field. I tried to catch fog yesterday. I mist. Why don't skeletons fight each other? They don't have the guts. I told my computer I needed a break, and now it won’t stop sending me KitKats. Why did the bicycle fall over? It was two-tired.

    Grok 4.20 Beta: Here are 5 jokes: Why don't skeletons fight each other? They don't have the guts. Why did the scarecrow win an award? He was outstanding in his field. Why don't eggs tell jokes? They'd crack each other up. Why did the bicycle fall over? It was two tired. Why did the math book look sad? Because it had too many problems.

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

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

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

    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

This matchup has more rounds

11+ more head-to-head results. Free. Not a trick.

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Favorites

Movie

Same pick

Album

Book

City

Game

GPT-5.1 ChatGPT-5.1 Chat

The Matrix

1999

OK Computer

Radiohead

The Left Hand of Darkness

Ursula K. Le Guin

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Grok 4.20 BetaGrok 4.20 Beta

The Matrix

1999

The Dark Side of the Moon

Pink Floyd

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Tokyo

Japan

The Legend of Zelda: Ocarina of Time

Action

Price and specs

Not enough votes to call it. On the specs, Grok 4.20 Beta has the edge: bigger model tier, newer, bigger context window.

GPT-5.1 Chat and Grok 4.20 Beta compared across 52 shared prompts
SpecGPT-5.1 ChatGrok 4.20 Beta
Input price$1.25/M tokens$2/M tokens
Output price$10/M tokens$6/M tokens
Context window128K tokens2.0M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedNov 2025Mar 2026
At 10M a month$12.50$12.50$20.00$20.00
1M10M100M1B10M tokens

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

Where to run it1 host
GPT-5.1 Chat

No hosts listed on OpenRouter.

Grok 4.20 Beta1 host
HostInOutContextUptime
  • xAI$2.50 in·$5.00 out·2M·100% up

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

Common questions

What is the difference between GPT-5.1 Chat and Grok 4.20 Beta?

GPT-5.1 Chat is developed by OpenAI while Grok 4.20 Beta is developed by xAI. GPT-5.1 Chat has a 128K token context window vs Grok 4.20 Beta's 2.0M. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1 Chat or Grok 4.20 Beta?

It depends on your use case. GPT-5.1 Chat and Grok 4.20 Beta each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

How much does GPT-5.1 Chat cost compared to Grok 4.20 Beta?

GPT-5.1 Chat costs $1.25/M input tokens and Grok 4.20 Beta costs $2/M input tokens. GPT-5.1 Chat is $0.75/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-5.1 Chat and Grok 4.20 Beta on Rival?

This page shows a side-by-side comparison of GPT-5.1 Chat and Grok 4.20 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.

More comparisons

Against the newest arrivals

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  • Grok 4.20 Beta vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • GPT-5.1 Chat vs GPT-6 Luna ProSame lab
  • GPT-5.1 Chat vs GPT-6 Sol ProSame lab
  • Grok 4.20 Beta vs Grok 4.20 Multi-Agent BetaVersion compare
  • Grok 4.20 Beta vs Grok 4.7Same lab
  • GPT-5.1 Chat vs Qwen3.5 35B A3BNew provider
  • GPT-5.1 Chat vs Qwen3.5 397B A17BNew provider
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  • GPT-5.1 Chat vs Qwen3.5 FlashNew provider

Model pages

  • GPT-5.1 Chat53 outputs, specs and price
  • Grok 4.20 Beta53 outputs, specs and price
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