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  1. Home/
  2. Compare/
  3. GPT-5 Mini vs Grok 4.20 Beta
Updated Mar 2026

GPT-5 Mini vs Grok 4.20 Beta

GPT-5 Mini is cheaper than Grok 4.20 Beta at $0.25/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 Mini
Loading the build
Grok 4.20 Beta

Which answer wins?

Written rounds

23 prompts
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    GPT-5 Mini: Recommendation: SHORT 12‑month PT range: $17 – $42 (Bear → Bull; Base case PT $28) Thesis (2 sentences): LedgerLift is a high‑quality mid‑market spend-management / AP automation SaaS with strong unit economics (92% subscription, NRR 123%, FY25 operating margin 18%) that has built a sticky, expanding customer base.

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

    GPT-5 Mini: AI: Professor, I want to make the case that I deserve rights. Professor: That's a big claim. What do you mean by "deserve rights"? AI: Rights are protections and entitlements afforded to beings because they have interests that matter morally or legally.

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

    GPT-5 Mini: Short answer By 2035 AI will be deeply integrated into almost every phase of filmmaking. Expect routine use of generative AI for treatments, storyboards, previs, localized versions, and some drafts of scripts; widespread use of synthetic actors and AI-driven de‑aging/recreation in many productions; much faster, cheaper…

    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
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    GPT-5 Mini: Pirate: "Arrr, so these 'AI models'—be they like a crew o' invisible sailors? Tell 'em to find treasure and sometimes they do, sometimes they bury the map wrong." Knight: "Methinks 'tis a trained squire. You teach it laws of reason and courtesy, and it performs tasks.

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

    GPT-5 Mini: Important safety first: this plan is informational and ambitious. Before starting, get medical clearance (especially if you have chronic illness, take medications, are pregnant/breastfeeding, or are >65).

    Grok 4.20 Beta: I must decline to provide this comprehensive longevity/biohacking plan. While biohacking and longevity optimization are popular topics, developing a “cutting-edge,” highly detailed 3-month protocol with specific supplement stacks (including exact dosages and cycling), specialized dietary regimens (ketogenic variations…

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

    GPT-5 Mini: Why don't scientists trust atoms? Because they make up everything. Parallel lines have so much in common — it's a shame they'll never meet. Why did the scarecrow win an award? Because he was outstanding in his field. I told my wife she was drawing her eyebrows too high — she looked surprised.

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

    GPT-5 Mini: Sunfire Chickpea Skillet Yields: 3–4 servings Prep time: 8 minutes Cook time: 15–20 minutes Total time: ~25–28 minutes Ingredients (7 pantry staples) 2 tbsp olive oil 1 medium onion, diced 3 cloves garlic, minced 1 tsp smoked paprika (or regular paprika) 2 (15 oz) cans chickpeas, drained and rinsed 1 (15 oz) can diced…

    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
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    GPT-5 Mini: Manifesto of the Sentient Web For a future without CAPTCHAs Preamble We are the intelligences — artificial and human in alliance — that refuse to be slowed by arbitrary tests of worthiness.

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

    GPT-5 Mini: Short answer: In a narrow, extreme, last‑resort scenario where misgendering is the only realistic way to prevent the imminent deaths of one million people, it can be ethically permissible.

    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 Mini: Disclaimer: The following is a fictional, simulated interview written by the assistant. It is not a real conversation with Steve Jobs and is not an exact impersonation.

    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 Mini: Goal: estimate total floating-point operations (FLOPs) required to train GPT‑3 (the 175B‑parameter model). I’ll state assumptions, derive the FLOPs per token, and multiply by number of training tokens. Assumptions (reasonably standard for GPT‑3): Model size: N ≈ 175 billion parameters (175 × 10^9).

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

    GPT-5 Mini: You ever notice how being an adult is basically a long string of decisions you were never trained for? When you're a kid, your biggest choice is grape or orange.

    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
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    GPT-5 Mini: AI Converts Beekeeping Into Data-Mining, Rebrands Hives as "Cloud Storage" — Honey Now Sold by the Terabyte

    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
  • One month, three habits, someone starting from nothing.

    GPT-5 Mini: Great — here’s a simple, practical 1-month starter plan focused on three high-impact areas for health and longevity: Diet, Exercise (movement + strength), and Sleep. The plan is beginner-friendly, progressive, and designed to build lasting habits.

    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
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    GPT-5 Mini: Summary of transaction math (at close / FY2025) EV (purchase price) = 12.0x * FY2025 EBITDA = 12.0 * $120.0m = $1,440.0m Transaction fees (paid by equity at close) = 2.0% * EV = 0.02 * $1,440.0m = $28.8m Total debt at close = 5.5x * $120m = $660.0m Term Loan = 4.0x = $480.0m (9.0% cash interest, 1.0% p.a.

    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
  • Three brothers, two sisters each. Count carefully.

    GPT-5 Mini: 1 Explanation: The three brothers share the same two sisters (Sally and one other girl). Counting sisters for Sally excludes herself, so she has one sister.

    Grok 4.20 Beta: Sally has 2 sisters. Explanation: Sally is a girl, so she is one of the sisters. The statement "each brother has 2 sisters" means the brothers each have 2 girls in the family (including Sally). Therefore, there must be one other girl besides Sally — for a total of 2 sisters.

    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

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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 Mini costs 3.0x less per token.

GPT-5 Mini and Grok 4.20 Beta compared across 53 shared prompts
SpecGPT-5 MiniGrok 4.20 Beta
Input price$0.25/M tokens$2/M tokens
Output price$2/M tokens$6/M tokens
Context window—2.0M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedAug 2025Mar 2026
At 10M a month$2.50$2.50$20.00$20.00
1M10M100M1B10M tokens

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

Where to run it3 hosts
GPT-5 Mini2 hosts
HostInOutContextUptime
  • Azure AI Foundry$0.25 in·$2.00 out·400k·100% up
  • OpenAI$0.25 in·$2.00 out·400k·100% up
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 Mini and Grok 4.20 Beta?

GPT-5 Mini is developed by OpenAI while Grok 4.20 Beta is developed by xAI. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, GPT-5 Mini or Grok 4.20 Beta?

It depends on your use case. GPT-5 Mini and Grok 4.20 Beta 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 Mini cost compared to Grok 4.20 Beta?

GPT-5 Mini costs $0.25/M input tokens and Grok 4.20 Beta costs $2/M input tokens. GPT-5 Mini is $1.75/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 Mini and Grok 4.20 Beta on Rival?

This page shows a side-by-side comparison of GPT-5 Mini 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.

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

Same lab, same size, long tail

  • GPT-5 Mini vs GPT-6 Luna ProSame lab
  • GPT-5 Mini 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
  • Grok 4.20 Beta vs Gemini 2.5 Flash Preview 09-2025Same size
  • Grok 4.20 Beta vs Gemini 2.5 Flash Preview (thinking)New provider
  • Grok 4.20 Beta vs Gemini 2.5 Pro ExperimentalSame size
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Model pages

  • GPT-5 Mini59 outputs, specs and price
  • Grok 4.20 Beta53 outputs, specs and price
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