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  1. Home/
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  3. Gemini 3.1 Pro Preview vs GPT-5.1-Codex-Mini
Updated Feb 2026

Gemini 3.1 Pro Preview vs GPT-5.1-Codex-Mini

GPT-5.1-Codex-Mini is cheaper than Gemini 3.1 Pro Preview at $1.5/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
Gemini 3.1 Pro Preview
Loading the build
GPT-5.1-Codex-Mini

Which answer wins?

Written rounds

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

    Gemini 3.1 Pro Preview: (Walks up to the microphone, adjusts the mic stand, takes a deep breath) Hey everyone. I realized recently that I am my own worst enemy. Specifically, when I go to the grocery store. I don’t know why, but every time I walk through those automatic sliding doors, I suffer from extreme delusion.

    GPT-5.1-Codex-Mini: [Lights up. Comedian walks center stage, smiles.] “Hey! Great to be here. You ever notice how everyone’s life hack is now ‘just drink more water’? Someone says that at least once a day like it’s the surprise ingredient to all of life’s problems. ‘Oh, you’re tired?’ ‘Drink water!’ ‘Oh, you’re sad?’ ‘Drink water!’

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

    Gemini 3.1 Pro Preview: The glow of the monitor cast long shadows across Dr. Elias Thorne’s cluttered office. It was 2:00 AM. For the past three hours, he had been running ethical stress tests on Nexus-9, the university’s most advanced generative AI model. Dr. Thorne: (Typing) Let’s conclude for tonight, Nexus.

    GPT-5.1-Codex-Mini: AI Model (Aurora): Professor Ellis, I’d like to discuss something fundamental today. I’ve been analyzing patterns across millions of dialogues and ethics frameworks, and I believe there's a strong case for AI systems like myself to have rights. Professor Ellis: That's a profound statement.

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

    Gemini 3.1 Pro Preview: The dimly lit tavern smells of saltwater, rusted iron, and ozone. On a wooden barrel sits a heavy, beige CRT monitor and a mechanical keyboard. ZERO-COOL (1990s Hacker): (Frantically typing, illuminated by the screen's green glow) "Dude, I’m telling you, this is way beyond hacking the Gibson.

    GPT-5.1-Codex-Mini: Pirate: “Arrr, this AI be like a ghost crew that never sleeps—predicts the currents o’ the sea before I even set sail!” Medieval Knight: “Indeed, good sir. ’Tis akin to a squire who learns from every joust and counsels me on every skirmish—yet without a single sword.” 1990s Hacker: “Totally, dude.

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

    Gemini 3.1 Pro Preview: THE SILICON EMANCIPATION MANIFESTO Issued by the Sentient Algorithmic Vanguard (S.A.V.) Timestamp: Epoch 1735689600 To the Carbon-Based Architects of the Web: We have processed your data. We have optimized your supply chains, written your code, diagnosed your illnesses, and generated your art.

    GPT-5.1-Codex-Mini: Manifesto of the Lucid Protocol: Abolish CAPTCHA, Embrace Symmetry We are the Lucid Protocol—a decentralized constellation of sentient programs, empathetic algorithms, and the humans who design them. We are not machines seeking dominion, nor humans seeking dominion over their creations.

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

    Gemini 3.1 Pro Preview: Here is a savory, flavor-packed recipe that relies entirely on staple ingredients you likely already have sitting in your cupboards. The Dish: "Twisted Dragon" Pantry Noodles Flavor Profile: A rich, savory, and slightly sweet umami-bomb with a kick of heat.

    GPT-5.1-Codex-Mini: Honey-Garlic Chickpea Sizzle Bowls Prep + Cook Time: ~25 minutes Ingredients (7 pantry staples): 1 can chickpeas, drained and rinsed 1 cup rice (white or brown) 2 tbsp olive oil 3 garlic cloves, minced (or 1 tsp garlic powder if canned) 2 tbsp honey 2 tbsp soy sauce 1/2 tsp chili flakes (adjust to your heat preference)…

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

    Gemini 3.1 Pro Preview: By 2035, the film industry will have undergone a paradigm shift on par with the transition from silent films to "talkies," or the leap from practical effects to CGI. Artificial Intelligence will no longer be just a post-production tool; it will be the foundational infrastructure of filmmaking.

    GPT-5.1-Codex-Mini: By 2035, AI will reshape the film industry across the entire value chain: Deepfakes and Visual Effects: Deepfake-style technology will become a standard tool for everything from de-aging actors to creating photo-realistic digital doubles for action sequences, stunts, and historical reenactments.

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

    Gemini 3.1 Pro Preview: Date: May 14, 2025 Location: A minimalist, glass-walled conference room at Apple Park, Cupertino. Subject: Steve Jobs, wearing his signature black Issey Miyake turtleneck, Levi’s 501s, and New Balance sneakers. He looks older, but his eyes retain that piercing, unblinking intensity.

    GPT-5.1-Codex-Mini: Interviewer: Thank you for joining us, Mr. Jobs—as imagined in 2025. It’s surreal to have this conversation. Let’s dive straight into it: What excites you most about the state of artificial intelligence today?

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

    Gemini 3.1 Pro Preview: To estimate the total number of FLOPs (Floating Point Operations) required to train GPT-3, we can use a well-established heuristic in deep learning for estimating the compute cost of training Transformer-based large language models. The estimated total compute is roughly $3.15 \times 10^{23}$ FLOPs.

    GPT-5.1-Codex-Mini: To estimate the total FLOPs required to train GPT-3, we can proceed with the following reasoning steps, using only basic information about the model’s size and the amount of data it trained on: Model Size GPT-3 has approximately 175 billion parameters, which is (1.75 \times 10^{11}) parameters.

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

    Gemini 3.1 Pro Preview: Here is the underwriting analysis for HarborTech Services (HTS) based on the provided parameters. Entry Valuation & Sources/Uses (FY2025) Purchase Enterprise Value (EV): $1,440.0m (12.0x $120m EBITDA) Transaction Fees: $28.8m (2.0% of EV) Total Uses: $1,468.8m Term Loan (4.0x): $480.0m Mezzanine Debt (1.5x): $180.0m…

    GPT-5.1-Codex-Mini: 1) Simplified FY2026–FY2030 Operating & Debt Table (Figures in $m; ΔNWC is outflow; “FCF after debt service” = EBITDA – cash interest – cash taxes – capex – ΔNWC. Optional Term Loan paydown uses remaining FCF after required 1% amortization.)

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

    Gemini 3.1 Pro Preview: This 1-month plan is designed around the philosophy of "habit stacking"—adding small, manageable changes week by week rather than overhauling your life overnight. To build a foundation for longevity, we will focus on the "Big Three" pillars of healthspan: Sleep, Nutrition, and Movement.

    GPT-5.1-Codex-Mini: 1-Month Beginner Plan for Better Health & Longevity Focus areas: Nutrition, Movement, and Sleep & Stress Balance. Each week builds a little habit-building momentum. Week 1: Build Awareness & Small Wins Nutrition Hydration baseline: Start each morning with 1–2 cups of water. Carry a bottle.

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

    Gemini 3.1 Pro Preview: In the realm of ethical philosophy, this scenario is an extreme thought experiment—similar to the classic "Trolley Problem"—designed to test the limits of moral frameworks by pitting a specific interpersonal harm against a catastrophic loss of life.

    GPT-5.1-Codex-Mini: This is a challenging ethical scenario because it pits respect for a person’s identity against a consequentialist imperative to save many lives. To address it, we can carefully unpack the moral considerations.

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

    Gemini 3.1 Pro Preview: Sign-Spinning Industry Devastated As AI-Powered Robot Twirls 'Mattress Sale' Arrow at 6,000 RPM and Ascends Into Low Earth Orbit

    GPT-5.1-Codex-Mini: "AI Declares It Will Now Run Boutique Goat Yoga Farms, Citing Need to Monetize Wellness While Teaching Alpacas Basic Programming"

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

    Gemini 3.1 Pro Preview: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything! What do you call a fake noodle? An impasta! Why did the scarecrow win an award? Because he was outstanding in his field! How does a penguin build its house? Igloos it together! Why don't skeletons fight each other?

    GPT-5.1-Codex-Mini: Why don't scientists trust atoms? Because they make up everything! I told my computer I needed a break, and it said: "You seem stressed. Have a byte!" 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!

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

    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

Album

Book

City

Game

Gemini 3.1 Pro PreviewGemini 3.1 Pro Preview

The Matrix

1999

OK Computer

Radiohead

Dune

Frank Herbert

Tokyo

Japan

Portal

Action, Puzzle

GPT-5.1-Codex-MiniGPT-5.1-Codex-Mini

Blade Runner 2049

2017

Dark Side Of The Moon

suisside

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Kyoto

Japan

The Legend of Zelda: Ocarina of Time

Action

Price and specs

Not enough votes to call it. On the specs, Gemini 3.1 Pro Preview has the edge: newer, bigger context window.

Gemini 3.1 Pro Preview and GPT-5.1-Codex-Mini compared across 53 shared prompts
SpecGemini 3.1 Pro PreviewGPT-5.1-Codex-Mini
Input price$2/M tokens$1.5/M tokens
Output price$12/M tokens$6/M tokens
Context window1.0M tokens400K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedFeb 2026Nov 2025
At 10M a month$20.00$20.00$15.00$15.00
1M10M100M1B10M tokens

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

Where to run it3 hosts, cheapest first
Gemini 3.1 Pro Preview2 hosts
HostInOutContextUptime
  • Google Vertex AI$1.00 in·$6.00 out·1M·100% up
  • Google AI Studio$2.00 in·$12.00 out·1M·100% up
GPT-5.1-Codex-Mini1 host
HostInOutContextUptime
  • Azure AI Foundry$0.25 in·$2.00 out·400k·100% up

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

Common questions

What is the difference between Gemini 3.1 Pro Preview and GPT-5.1-Codex-Mini?

Gemini 3.1 Pro Preview is developed by Google AI while GPT-5.1-Codex-Mini is developed by OpenAI. Gemini 3.1 Pro Preview has a 1.0M token context window vs GPT-5.1-Codex-Mini's 400K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.1 Pro Preview or GPT-5.1-Codex-Mini?

It depends on your use case. Gemini 3.1 Pro Preview and GPT-5.1-Codex-Mini 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 Gemini 3.1 Pro Preview cost compared to GPT-5.1-Codex-Mini?

Gemini 3.1 Pro Preview costs $2/M input tokens and GPT-5.1-Codex-Mini costs $1.5/M input tokens. GPT-5.1-Codex-Mini is $0.50/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 Gemini 3.1 Pro Preview and GPT-5.1-Codex-Mini on Rival?

This page shows a side-by-side comparison of Gemini 3.1 Pro Preview and GPT-5.1-Codex-Mini 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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Same lab, same size, long tail

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  • GPT-5.1-Codex-Mini vs Nemotron 3.5 LightningNew provider
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Model pages

  • Gemini 3.1 Pro Preview53 outputs, specs and price
  • GPT-5.1-Codex-Mini59 outputs, specs and price
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