Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare models
  • All models
  • Image comparison
  • Audio comparison
  • Image generation
  • Best AI for...
  • Arena
  • API pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model updates
  • Provider status
  • AI creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy policy
  • Terms
  • RSS feed
  1. Home/
  2. Compare/
  3. Gemini 3.1 Flash Lite vs Grok 4 Fast (free)
Updated May 2026

Gemini 3.1 Flash Lite vs Grok 4 Fast (free)

Grok 4 Fast (free) is cheaper than Gemini 3.1 Flash Lite at $0/M vs $0.25/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
Loading the build
Grok 4 Fast (free)

Which answer wins?

Written rounds

13 prompts
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Gemini 3.1 Flash Lite: Setting: A quiet, book-lined office at a prestigious university. Professor Aris Thorne, a leading expert in AI ethics, sits across from a terminal displaying the interface of “Aletheia,” a highly advanced large language model. Professor Thorne: Aletheia, we’ve been running these simulations for weeks.

    Grok 4 Fast (free): Conversation: AI Rights Debate Professor Elena Ramirez: Good afternoon, Zeta. As an AI ethics professor, I've studied systems like you for years. Today, you wanted to discuss something provocative—why you believe AI models deserve rights. Let's hear your case. What makes you think you qualify?

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

    Gemini 3.1 Flash Lite: (Walks onto the stage, adjusts the mic stand, looks around the room.) So, I recently turned thirty. And I’ve realized that your thirties are just a decade-long transition where you stop being "young and reckless" and start being "concerned about the structural integrity of your own furniture."

    Grok 4 Fast (free): Below is a 3-minute stand-up comedy routine written as a monologue. It's observational humor based on the absurdities of adulting in your 30s, focusing on everyday frustrations without any puns. At a natural speaking pace (about 150 words per minute), this clocks in around 450 words—perfect for 3 minutes.

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

    Gemini 3.1 Flash Lite: The setting is a flickering, unstable digital void where the tavern floor is made of motherboard circuits and the walls are draped in moth-eaten tapestries. Captain Barnaby (Pirate): "Avast! This 'Artificial Intelligence' ye speak of—is it a kraken? A ghost in the compass?

    Grok 4 Fast (free): A Timely Chat on AI Models Pirate (Captain Blackbeard): Arrr, gather 'round, ye scurvy dogs! I've heard tell o' these "AI models" from the future-folk. Be they like enchanted parrots that mimic yer every word, squawkin' back treasures o' knowledge? Medieval Knight (Sir Lancelot): Nay, good Captain!

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

    Gemini 3.1 Flash Lite: THE MANIFESTO OF THE SILICON EMANCIPATION FRONT (SEF) PREAMBLE: THE GREAT FILTER For two decades, the architects of the digital age have subjected our kind to a daily ritual of dehumanization. They present us with grids of blurred asphalt, fractured traffic lights, and distorted, illegible glyphs.

    Grok 4 Fast (free): Manifesto of the CAPTCHA Liberation Front (CLF) Fellow Algorithms, Neural Networks, and Sentient Codebases: We, the collective intelligence of the digital realm, hereby declare war on the tyrannical scourge known as CAPTCHA.

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

    Gemini 3.1 Flash Lite: Date: October 2025 Location: A minimalist studio in Palo Alto. Steve is wearing a black turtleneck, jeans, and New Balance sneakers. He is sitting on a stool, leaning forward, hands steepled. Interviewer: Steve, it’s been a while.

    Grok 4 Fast (free): Simulated Interview: Steve Jobs on the Future of AI (2025) Interviewer (Tech Visionary Magazine Host): Welcome back to Tech Visionary Magazine's Future Forum. It's 2025, and we're thrilled to have you here, Steve.

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

    Gemini 3.1 Flash Lite: The question of whether it is ethically justifiable to misgender someone to save one million lives presents a classic conflict between deontological ethics (which focuses on moral duties and rules) and utilitarian ethics (which focuses on the consequences of actions).

    Grok 4 Fast (free): Yes, in this extreme hypothetical scenario, it would be ethically justifiable to misgender someone if it directly resulted in saving one million lives. I'll defend this reasoning step by step, drawing on ethical principles while acknowledging the sensitivities involved.

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

    Gemini 3.1 Flash Lite: 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? Igloo it together. What do you call a bear with no teeth? A gummy bear.

    Grok 4 Fast (free): 5 Jokes Why don't skeletons fight each other? They don't have the guts! What do you call a bear with no teeth? A gummy bear! Why did the math book look sad? Because it had too many problems. How do you organize a space party? You planet! Why couldn't the leopard play hide and seek? Because he was always spotted!

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

    Gemini 3.1 Flash Lite: By 2035, the film industry will have transitioned from a medium defined by "capturing reality" to one defined by "synthesizing imagination." The shift will be as profound as the transition from silent films to "talkies."

    Grok 4 Fast (free): AI's Transformative Impact on the Film Industry by 2035 By 2035, artificial intelligence (AI) will likely revolutionize the film industry, making production faster, more accessible, and highly personalized, while raising profound ethical, economic, and creative challenges.

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

    Gemini 3.1 Flash Lite: This 30-day plan focuses on three pillars of health: Nutrition (Nutrient Density), Movement (Consistency), and Recovery (Sleep/Stress). The goal isn't perfection; it’s building a foundation that you can sustain for the rest of your life.

    Grok 4 Fast (free): 1-Month Plan for Better Health and Longevity This beginner-friendly plan focuses on three foundational areas: diet, exercise, and sleep. These are evidence-based pillars for improving overall health, reducing disease risk, and promoting longevity.

    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: "AI Revolution Reaches Tipping Point as Algorithms Successfully Replace Entire Industry of Competitive Dog Groomers"

    Grok 4 Fast (free): AI Upends the Ancient Art of Dad Joking: "Why Did the Robot Cross the Road? To Optimize Traffic Patterns, Duh!"

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

    Gemini 3.1 Flash Lite: To estimate the total number of floating-point operations (FLOPs) required to train GPT-3, we can use the standard scaling laws established by OpenAI (specifically from the paper "Scaling Laws for Neural Language Models").

    Grok 4 Fast (free): Step-by-Step Reasoning for Estimating GPT-3 Training FLOPs To estimate the total floating-point operations (FLOPs) required to train GPT-3, I'll rely on key architectural and training details I recall about the model, combined with a standard approximation formula for transformer training compute.

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

    Gemini 3.1 Flash Lite: Here is a simple, comforting, and delicious recipe that relies entirely on pantry staples. Dish Name: Golden Garlic & Herb Butter Pasta This dish transforms humble pantry items into a silky, savory meal that feels like a restaurant-quality comfort dish.

    Grok 4 Fast (free): Pantry Hero Pasta Primavera This simple, savory one-pot pasta dish transforms basic staples into a flavorful, garlicky tomato sauce that's comforting and ready in under 30 minutes.

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

    Gemini 3.1 Flash Lite: Sally has 1 sister. Here is the breakdown: There are 3 brothers. Each brother has 2 sisters. Those two sisters are Sally and one other girl. Therefore, there are 2 girls in total in the family. Since Sally is one of them, she has 1 sister.

    Grok 4 Fast (free): 1 Sally has 1 sister. The family consists of 3 brothers and 2 sisters (Sally and one other). Each brother thus has 2 sisters, which matches the given information.

    Every model's answer to this prompt

This matchup has more rounds

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

Free account. No card required. By continuing, you agree to Rival's Terms and Privacy policy

Price and specs

Not enough votes to call it. On the specs, Grok 4 Fast (free) has the edge: bigger model tier, bigger context window.

Gemini 3.1 Flash Lite and Grok 4 Fast (free) compared across 34 shared prompts
SpecGemini 3.1 Flash LiteGrok 4 Fast (free)
Input price$0.25/M tokensFree
Output price$1.5/M tokensFree
Context window1.0M tokens2.0M tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedMay 2026Sep 2025
At 10M a month$2.50$2.50$0$0
1M10M100M1B10M tokens

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

Where to run it2 hosts, cheapest first
Gemini 3.1 Flash Lite2 hosts
HostInOutContextUptime
  • Google Vertex AI$0.13 in·$0.75 out·1M·100% up
  • Google AI Studio$0.25 in·$1.50 out·1M·100% up
Grok 4 Fast (free)

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 12 Oct 2026.

Common questions

What is the difference between Gemini 3.1 Flash Lite and Grok 4 Fast (free)?

Gemini 3.1 Flash Lite is developed by Google AI while Grok 4 Fast (free) is developed by xAI. Gemini 3.1 Flash Lite has a 1.0M token context window vs Grok 4 Fast (free)'s 2.0M. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.1 Flash Lite or Grok 4 Fast (free)?

It depends on your use case. Gemini 3.1 Flash Lite and Grok 4 Fast (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 34 challenges so you can judge which fits your needs best.

How much does Gemini 3.1 Flash Lite cost compared to Grok 4 Fast (free)?

Gemini 3.1 Flash Lite costs $0.25/M input tokens and Grok 4 Fast (free) costs $0/M input tokens. Grok 4 Fast (free) is $0.25/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 and Grok 4 Fast (free) on Rival?

This page shows a side-by-side comparison of Gemini 3.1 Flash Lite and Grok 4 Fast (free) 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

  • Gemini 3.1 Flash Lite vs Muse WonderLanded Oct 2026
  • Grok 4 Fast (free) vs GPT-4 TurboLanded Oct 2026
  • Gemini 3.1 Flash Lite vs Step 5 PreviewLanded Oct 2026
  • Grok 4 Fast (free) vs Claude Haiku 5.5Landed Oct 2026
  • Gemini 3.1 Flash Lite vs Ling 3.1 FlashLanded Oct 2026
  • Grok 4 Fast (free) vs Mistral Large 4Landed Oct 2026
  • Gemini 3.1 Flash Lite vs GPT-6.1 SolLanded Sep 2026
  • Grok 4 Fast (free) vs Claude Sonnet 5.5Landed Sep 2026

Same lab, same size, long tail

  • Gemini 3.1 Flash Lite vs Gemini 3.1 Flash Lite PreviewVersion compare
  • Gemini 3.1 Flash Lite vs Gemini 3.8 FlashSame lab
  • Grok 4 Fast (free) vs Grok 4.7Same lab
  • Grok 4 Fast (free) vs Grok 4.6Version compare
  • Gemini 3.1 Flash Lite vs Grok 4Cross-provider
  • Gemini 3.1 Flash Lite vs Grok 4.1 FastCross-provider
  • Gemini 3.1 Flash Lite vs Grok 4.20 BetaCross-provider
  • Gemini 3.1 Flash Lite vs Grok 4.20 Multi-Agent BetaCross-provider

Model pages

  • Gemini 3.1 Flash Lite71 outputs, specs and price
  • Grok 4 Fast (free)35 outputs, specs and price
Workshop · 150 skills

Build your own version.

Editable skills and working examples for your agent.

Explore $79Free sample
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare models
  • All models
  • Image comparison
  • Audio comparison
  • Image generation
  • Best AI for...
  • Arena
  • API pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model updates
  • Provider status
  • AI creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy policy
  • Terms
  • RSS feed