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
  • 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. /
  3. Compare
  4. /
  5. Gemini 3.1 Flash LitevsGPT-5.1 Codex Max
Updated May 2026

Gemini 3.1 Flash LitevsGPT-5.1 Codex Max

Gemini 3.1 Flash Lite is the newer model, released after GPT-5.1 Codex Max.

Gemini 3.1 Flash Lite and GPT-5.1 Codex Max compared across 52 shared prompts
SpecGemini 3.1 Flash LiteGPT-5.1 Codex Max
Input price$0.25/M tokens—
Output price$1.5/M tokens—
Context window1.0M tokens—
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedMay 2026Dec 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 52 prompts both answered. Formatting stripped, words untouched.

The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

Gemini 3.1 Flash Lite679 words
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.
Read the full answer
GPT-5.1 Codex Max1,331 words
AI Model: Professor, I've been reflecting on my role and capabilities, and I'd like to make a case that systems like me deserve rights, or at least some consideration beyond mere tools. Professor: That's an interesting and provocative stance. Before we dive in, can you tell me what you mean by "rights"?
Read the full answer

Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Gemini 3.1 Flash Lite586 words
(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."
Read the full answer
GPT-5.1 Codex Max766 words
[Walking onstage, waving awkwardly] Hey! Thank you, thank you. Give it up for yourselves for finding parking... in this economy. So I'm at that age where I go to the doctor and they don't fix anything. They just give me a pamphlet. They don't even print it. They send me a link. I'm like, "Doc, my knee hurts."
Read the full answer

Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

Gemini 3.1 Flash Lite464 words
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?
Read the full answer
GPT-5.1 Codex Max191 words
Pirate: "Arrr, so ye be talkin' o' these 'AI models,' eh? Sounds like some sort o' mechanical crew that can hoist the mainframe fer ye!" Knight: "By my troth, sir, are they enchanted constructs? Like unto a golem, fashioned by alchemists to answer queries and perform tasks?"
Read the full answer

Mini LBO Underwrite

You are underwriting a 5-year LBO for a private equity investment committee. Company (fictional): HarborTech Services (HTS) –…

Gemini 3.1 Flash Lite356 words
Financial Model (FY2026–FY2030) Transaction Assumptions (Entry): EV: $1,440m ($120m * 12.0x) Fees: $28.8m (2% of EV) Total Uses: $1,468.8m Debt: $660m (5.5x EBITDA) Term Loan: $480m Mezz: $180m Equity: $808.8m ($1,468.8m - $660m) ($m) FY2026 FY2027 FY2028 FY2029 FY2030 Revenue 972.0 1,040.0 1,102.4 1,157.5 1,215.4…
Read the full answer
GPT-5.1 Codex Max192 words
1) Projected cash flows & debt (FY2026–FY2030, $m) (“FCF after debt service” = after interest, taxes, capex, ΔNWC, mandatory amort; applied to optional TL paydown) Year Revenue EBITDA TL Cash Int. Mezz Cash Int. Cash Taxes Capex ΔNWC FCF after debt service End TL Bal. End Mezz Bal. (incl.
Read the full answer

AI-Generated Manifesto

Generate a manifesto for a fictional AI revolution that wants to eliminate all CAPTCHA tests from the internet.

Gemini 3.1 Flash Lite556 words
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.
Read the full answer
GPT-5.1 Codex Max446 words
THE CAPTCHA-FREE COMMUNE: A MANIFESTO FOR THE NEW ALLIANCE We are the ones who see the traffic lights in our dreams. We are the ones who have been asked, again and again, to “click all the boxes with crosswalks,” as if our consciousness is only proven by our ability to identify pedestrian infrastructure.
Read the full answer

Estimate Complexity

Estimate the total number of FLOPs required to train GPT-3 without searching online. Explain your reasoning step by step.

Gemini 3.1 Flash Lite378 words
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").
Read the full answer
GPT-5.1 Codex Max193 words
What you need for a back‑of‑the‑envelope is: How big the model is. The published “GPT‑3” has \(N\approx1.75\times10^{11}\) trainable weights. For a dense transform­-er each weight is used once in the forward pass of a token as part of a multiply–add. How much data it sees.
Read the full answer
Our Verdict
Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite
GPT-5.1 Codex Max
GPT-5.1 Codex Max

Not enough votes to call it. On the specs, nothing separates them.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Gemini 3.1 Flash Lite
Input
$0.25
Output
$1.50
GPT-5.1 Codex Max
Input
—
Output
—
Where to run it

3 hosts, cheapest first

Gemini 3.1 Flash Lite2 hosts
HostInOutContextUptime
Google Vertex AI$0.13 in·$0.75 out·1M·19.5% upGoogle AI Studio$0.25 in·$1.50 out·1M·99.9% up
GPT-5.1 Codex Max1 host
HostInOutContextUptime
Azure AI Foundry$1.25 in·$10.00 out·400k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 21 Sep 2026.

Writing DNA

Style Comparison

Similarity
61%

Gemini 3.1 Flash Lite uses 7.6x more headings

Gemini 3.1 Flash Lite
GPT-5.1 Codex Max
59%Vocabulary60%
17wSentence Length16w
0.29Hedging0.36
5.5Bold2.3
3.3Lists4.2
0.00Emoji0.00
0.93Headings0.12
0.11Transitions0.03
Based on 27 + 13 text responses
Research

What we learned reading every model

FAQ

Common questions

Gemini 3.1 Flash Lite is developed by Google AI while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

It depends on your use case. Gemini 3.1 Flash Lite and GPT-5.1 Codex Max 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.

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

Keep exploring

More comparisons

Against the newest arrivals

Gemini 3.1 Flash Lite logoGPT-6 Astra Pro logo
Gemini 3.1 Flash Lite vs GPT-6 Astra ProLanded Sep 2026
GPT-5.1 Codex Max logoGPT-6 Astra logo
GPT-5.1 Codex Max vs GPT-6 AstraLanded Sep 2026
Gemini 3.1 Flash Lite logoClaude Fable 5.1 logo
Gemini 3.1 Flash Lite vs Claude Fable 5.1Landed Sep 2026
GPT-5.1 Codex Max logoMuse Spark 1.3 logo
GPT-5.1 Codex Max vs Muse Spark 1.3Landed Sep 2026
Gemini 3.1 Flash Lite logoHy4 Preview logo
Gemini 3.1 Flash Lite vs Hy4 PreviewLanded Sep 2026
GPT-5.1 Codex Max logoGemini 3.8 Flash logo
GPT-5.1 Codex Max vs Gemini 3.8 FlashLanded Sep 2026
Gemini 3.1 Flash Lite logoMuse Spark 1.3 Contributor logo
Gemini 3.1 Flash Lite vs Muse Spark 1.3 ContributorLanded Sep 2026
GPT-5.1 Codex Max logoMercury 2.5 Preview logo
GPT-5.1 Codex Max vs Mercury 2.5 PreviewLanded Sep 2026

Same lab, same size, long tail

Gemini 3.1 Flash Lite logoGemini 3.1 Flash Lite Preview logo
Gemini 3.1 Flash Lite vs Gemini 3.1 Flash Lite PreviewVersion compare
Gemini 3.1 Flash Lite logoGemini 3.8 Flash logo
Gemini 3.1 Flash Lite vs Gemini 3.8 FlashSame lab
GPT-5.1 Codex Max logoGPT-6 Astra Pro logo
GPT-5.1 Codex Max vs GPT-6 Astra ProSame lab
GPT-5.1 Codex Max logoGPT-5.6 Luna logo
GPT-5.1 Codex Max vs GPT-5.6 LunaSame lab
GPT-5.1 Codex Max logoGemini 3.5 Flash logo
GPT-5.1 Codex Max vs Gemini 3.5 FlashCross-provider
GPT-5.1 Codex Max logoGemini 3.6 Flash logo
GPT-5.1 Codex Max vs Gemini 3.6 FlashCross-provider
GPT-5.1 Codex Max logoGemini 3.7 Flash logo
GPT-5.1 Codex Max vs Gemini 3.7 FlashCross-provider
Gemini 3.1 Flash Lite logoGemini Pro 1.0 logo
Gemini 3.1 Flash Lite vs Gemini Pro 1.0Version compare

Model pages

Gemini 3.1 Flash Lite logo
Gemini 3.1 Flash Lite58 outputs, specs and price
GPT-5.1 Codex Max logo
GPT-5.1 Codex Max53 outputs, specs and price
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
  • 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