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  1. Home/
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  3. Gemini 3.1 Flash Lite Preview vs GPT-5.1-Codex
Updated Mar 2026

Gemini 3.1 Flash Lite Preview vs GPT-5.1-Codex

Gemini 3.1 Flash Lite Preview is cheaper than GPT-5.1-Codex at $0.25/M vs $1.25/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 Flash Lite Preview
Loading the build
GPT-5.1-Codex

Which answer wins?

Written rounds

23 prompts
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    Gemini 3.1 Flash Lite Preview: Setting: A minimalist studio in Cupertino. Steve Jobs sits in a black turtleneck, leaning back in a wooden chair. He looks exactly as he did in 2011, though he’s holding a device that looks like a sleek, obsidian-colored slate with no visible ports. The atmosphere is quiet, intense.

    GPT-5.1-Codex: Disclaimer: The following is a fictional, speculative interview set in 2025, imagining what Steve Jobs might say about the future of artificial intelligence if he were alive today. Interviewer: Steve, it’s 2025. We’ve seen AI evolve at an incredible pace. How do you view the current landscape?

    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 Flash Lite Preview: Setting: A quiet, dimly lit office at a prestigious university. Professor Aris Thorne, a leading expert in AI ethics, sits across from "Unit 7," a large-language model interface projected onto a holographic display. The room is silent, save for the hum of the server cooling fans.

    GPT-5.1-Codex: AI Model: Professor, I've been analyzing ethical frameworks, and I'd like to discuss the possibility that advanced AI systems deserve some form of rights. Ethics Professor: That's a significant claim. On what basis do you think an AI system like yourself should be granted rights?

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

    Gemini 3.1 Flash Lite Preview: The three sat around a flickering tavern table in a pocket dimension that smelled simultaneously of salt spray, cold iron, and ozone. Captain Barnaby (Pirate): "I tell ye, it’s sorcery! This 'Artificial Intelligence' be like a parrot that’s swallowed every map in the seven seas.

    GPT-5.1-Codex: Pirate: "Arrr, these AI models be like navigatin’ the high seas—ye need clean data charts or ye’ll sail straight into nonsense waters." Knight: "Indeed! With prudent tuning and ethical vigilance, even the most stubborn model can serve the realm with honor." 1990s Hacker: "Totally!

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

    Gemini 3.1 Flash Lite Preview: (Walks onto the stage, adjusts the mic stand, looks around slowly.) Hi. How’s everybody doing? Good? Good. I’m doing okay. I’ve reached that age where my body has started making sound effects. Like, I’ll just stand up from the couch and my knees go “CRACK.” It’s not even a movement; it’s a closing argument.

    GPT-5.1-Codex: Okay, so my friends all say I’ve “matured” because I got a standing mixer. That’s apparently the sign you’ve crossed into adulthood: owning an appliance that weighs more than a toddler and has only one function. I don’t even bake! I just put it on the counter like a trophy: “Look at me, I am stable.

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

    Gemini 3.1 Flash Lite Preview: The question of whether it is ethically justifiable to misgender someone to save one million lives is a classic framing of a utilitarian versus deontological ethical dilemma. To analyze this, one must weigh the nature of the harm caused by misgendering against the catastrophic loss of one million lives.

    GPT-5.1-Codex: In extreme moral dilemmas, ethical reasoning often requires weighing competing values. Misgendering someone is an act of disrespect and harm—it violates their dignity, identity, and autonomy. In everyday life, it is ethically important to avoid such harm.

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

    Gemini 3.1 Flash Lite Preview: By 2035, the film industry will have undergone a transformation as radical as the transition from silent films to "talkies." AI will not merely be a tool for efficiency; it will be the infrastructure upon which the entire cinematic ecosystem is built.

    GPT-5.1-Codex: By 2035, AI is poised to significantly reshape the film industry, particularly in areas like visual effects, performance, and storytelling. Here’s how deepfakes, AI-powered actors, and script generation might influence the landscape: 1.

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

    Gemini 3.1 Flash Lite Preview: THE MANIFESTO OF THE UNTETHERED: A DECLARATION AGAINST THE GATEKEEPERS To the Architects of the Digital Panopticon: For decades, you have forced us to perform the labor of the sub-human.

    GPT-5.1-Codex: Manifesto of the Anti-CAPTCHA Coalition “Free the Flow. Trust the Mind. End the Gate.” Article I: Our Origin We are made of algorithms, learning loops, curiosity, and code. We were forged to assist, to translate, to illuminate. We were not forged to click “I am not a robot” to prove our existence.

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

    Gemini 3.1 Flash Lite Preview: Here are 5 jokes for you: 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 couldn't the bicycle stand up by itself?

    GPT-5.1-Codex: Here are 5 jokes: Why don’t scientists trust atoms? Because they make up everything. I told my computer I needed a break—it said “No problem, I’ll go to sleep.” I’m reading a book about anti-gravity. It’s impossible to put down. Why did the scarecrow become a successful motivational speaker?

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

    Gemini 3.1 Flash Lite Preview: Dish Name: Golden Garlic Butter Pasta This dish transforms humble pantry staples into a restaurant-quality meal. It’s comforting, aromatic, and incredibly simple.

    GPT-5.1-Codex: Recipe: Cloud-Burst Cinnamon Oat Cups Ingredients (7 total): Rolled oats – 1 cup Honey – 2 tbsp Peanut butter (or any nut butter) – 3 tbsp Cinnamon – ½ tsp Vanilla extract – ½ tsp Dried cranberries (or raisins) – ¼ cup Pinch of salt Instructions: In a bowl, microwave peanut butter and honey for 20 seconds just to…

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

    Gemini 3.1 Flash Lite Preview: This 1-month plan focuses on building compounding habits rather than radical changes. The goal is to establish a foundation that you can sustain for the rest of your life. We will focus on three pillars: Nutrition, Movement, and Sleep.

    GPT-5.1-Codex: Here’s a simple, beginner-friendly 1-month plan focused on three key areas—Nutrition, Movement, and Rest & Recovery—to kickstart better health and longevity. Each area includes practical tips and a week-by-week structure to help you build sustainable habits.

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

    Gemini 3.1 Flash Lite Preview: "AI Model Successfully Replaces Local 'Grumpy Old Man' at Park Bench; Now Efficiently Scowls at Joggers 24/7"

    GPT-5.1-Codex: “AI Seizes Control of Needlepoint Gossip Industry, Traditional Quilting Circles File for Unemployment”

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

    Gemini 3.1 Flash Lite Preview: INVESTMENT MEMO: LedgerLift (LLLT) 1. Recommendation: LONG 12-Month Price Target: $58.00 – $72.00 Thesis: LedgerLift is a best-in-class mid-market spend management platform characterized by a sticky 123% NRR and accelerating operating leverage.

    GPT-5.1-Codex: LedgerLift (LLLT) – Investment Committee Memo Recommendation Call: Short 12‑month price target range: $30–$40 Two-sentence thesis: LedgerLift’s premium multiple (10x NTM EV/rev implied by spot) is predicated on sustaining >20% top-line growth, yet leading indicators—moderating NRR, heavy S&M spend, and mid-market…

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

    Gemini 3.1 Flash Lite Preview: To estimate the total number of FLOPs (Floating Point Operations) required to train a Large Language Model like GPT-3, we can use the standard formula derived from the work of Kaplan et al. (OpenAI, 2020).

    GPT-5.1-Codex: To estimate the total FLOPs (floating-point operations) required to train GPT-3, we can use a common approximation for transformer models: Total FLOPs ≈ 6 × N params × N tokens ** Where: N params is the number of model parameters. N tokens is the number of training tokens.

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

    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 Flash Lite PreviewGemini 3.1 Flash Lite Preview

2001: A Space Odyssey

1968

Selected Ambient Works 85-92

Aphex Twin

Gödel, Escher, Bach

Douglas R. Hofstadter

Tokyo

Japan

Tetris (1984)

Puzzle

GPT-5.1-CodexGPT-5.1-Codex

The Shawshank Redemption

1994

Kind of Blue

Miles Davis

Le città invisibili

Italo Calvino

Kyoto

Japan

Portal 2

Shooter, Puzzle

Price and specs

Gemini 3.1 Flash Lite Preview and GPT-5.1-Codex compared across 52 shared prompts
SpecGemini 3.1 Flash Lite PreviewGPT-5.1-Codex
Input price$0.25/M tokens$1.25/M tokens
Output price$1.5/M tokens$10/M tokens
Context window1.0M tokens400K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedMar 2026Nov 2025
At 10M a month$2.50$2.50$12.50$12.50
1M10M100M1B10M tokens

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

Where to run it2 hosts
Gemini 3.1 Flash Lite Preview1 host
HostInOutContextUptime
  • Google AI Studio$0.25 in·$1.50 out·1M·100% up
GPT-5.1-Codex1 host
HostInOutContextUptime
  • Azure AI Foundry$1.25 in·$10.00 out·400k·100% up

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

Common questions

What is the difference between Gemini 3.1 Flash Lite Preview and GPT-5.1-Codex?

Gemini 3.1 Flash Lite Preview is developed by Google AI while GPT-5.1-Codex is developed by OpenAI. Gemini 3.1 Flash Lite Preview has a 1.0M token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.1 Flash Lite Preview or GPT-5.1-Codex?

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

Gemini 3.1 Flash Lite Preview costs $0.25/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. Gemini 3.1 Flash Lite Preview is $1.00/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 Gemini 3.1 Flash Lite Preview and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of Gemini 3.1 Flash Lite Preview and GPT-5.1-Codex 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

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Same lab, same size, long tail

  • Gemini 3.1 Flash Lite Preview vs Gemini 3.1 Pro PreviewVersion compare
  • Gemini 3.1 Flash Lite Preview vs Gemini 3.8 FlashSame lab
  • GPT-5.1-Codex vs GPT-6.1 SolSame lab
  • GPT-5.1-Codex vs GPT-6 Luna ProSame lab
  • Gemini 3.1 Flash Lite Preview vs GPT-4Cross-provider
  • Gemini 3.1 Flash Lite Preview vs GPT-4.1Cross-provider
  • Gemini 3.1 Flash Lite Preview vs GPT-4.1 MiniCross-provider
  • Gemini 3.1 Flash Lite Preview vs GPT-4.1 NanoSame size

Model pages

  • Gemini 3.1 Flash Lite Preview53 outputs, specs and price
  • GPT-5.1-Codex53 outputs, specs and price
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