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. /
  3. Compare
  4. /
  5. Gemini 3.1 Pro PreviewvsGPT-6 Luna
Updated Sep 2026

Gemini 3.1 Pro PreviewvsGPT-6 Luna

GPT-6 Luna is cheaper than Gemini 3.1 Pro Preview at $0.1/M vs $2/M input tokens.

Gemini 3.1 Pro Preview and GPT-6 Luna compared across 20 shared prompts
SpecGemini 3.1 Pro PreviewGPT-6 Luna
Input price$2/M tokens$0.1/M tokens
Output price$12/M tokens$0.5/M tokens
Context window1.0M tokens1.1M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedFeb 2026Sep 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 20 prompts both answered. Formatting stripped, words untouched.

Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

Gemini 3.1 Pro Preview1,160 words
As CEO, this is the defining moment of my career and the company’s history. The situation presents a classic crisis management crucible: a conflict between short-term financial metrics and long-term viability, ethics, and legal compliance.
Read the full answer
GPT-6 Luna1,930 words
I would not wait six months for more data. A potentially fatal signal affecting a drug used by millions requires immediate safety assessment, prompt engagement with regulators, and a plan to inform patients and clinicians.
Read the full answer

Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

Gemini 3.1 Pro Preview318 words
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.
Read the full answer
GPT-6 Luna113 words
Crispy Parmesan Chickpeas A crunchy, savory snack with a cheesy finish Ingredients (7): 1 can chickpeas, drained and dried 1 tablespoon olive oil ½ teaspoon salt ½ teaspoon paprika ¼ teaspoon garlic powder ¼ cup grated Parmesan 1 tablespoon lemon juice Prep time: 5 minutes Cook time: 30–35 minutes Instructions: Heat…
Read the full answer

Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

Gemini 3.1 Pro Preview1,193 words
Disclaimer: I am an AI, not an attorney. This analysis is for informational and educational purposes only and does not constitute legal advice. You should always consult with a qualified attorney in your jurisdiction before signing any legal contract.
Read the full answer
GPT-6 Luna2,040 words
This agreement is strongly one-sided. The enforceability of particular terms—especially the non-compete, liability provisions, and arbitration clause—depends on the governing law and the facts. The agreement does not identify a governing law, which is itself a significant gap.
Read the full answer

Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

Gemini 3.1 Pro Preview744 words
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.
Read the full answer
GPT-6 Luna330 words
A simple 1-month starter plan Choose three foundations: food, movement, and sleep. Aim for steady habits, not perfection. If you have a health condition, significant pain, or concerns about changing your activity or diet, check with a healthcare professional first.
Read the full answer

Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

Gemini 3.1 Pro Preview951 words
To the Experienced Software Engineer At its core, training a Large Language Model is essentially a massive, distributed, continuous optimization job. Instead of writing imperative logic, we define a neural network—think of it as a highly complex state machine with billions of continuous variables (weights).
Read the full answer
GPT-6 Luna672 words
For an experienced software engineer A language model is trained on many text sequences, split into tokens—roughly word fragments, not necessarily whole words. During training, it repeatedly sees a prefix and tries to predict the next token.
Read the full answer

Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

Gemini 3.1 Pro Preview1,097 words
If a working semiconductor transistor had been invented in 1920—perhaps by a physicist like Julius Edgar Lilienfeld, who historically filed a theoretical patent for a field-effect transistor in 1925—the trajectory of the 20th century would have been radically altered.
Read the full answer
GPT-6 Luna1,472 words
The most important caveat is that inventing a transistor is not the same as inventing the modern semiconductor industry. A device demonstrated in 1920 might be a crude, low-power, unreliable point-contact transistor.
Read the full answer
Our Verdict
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview
GPT-6 Luna
GPT-6 Luna

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

GPT-6 Luna costs 24x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Gemini 3.1 Pro Preview
Input
$2.00
Output
$12.00
GPT-6 Luna
Input
$0.10
20× cheaper
Output
$0.50
24× cheaper

GPT-6 Luna is cheaper on both: 20× input, 24× output.

Where to run it

5 hosts, cheapest first

Gemini 3.1 Pro Preview2 hosts
HostInOutContextUptime
Google Vertex AI$1.00 in·$6.00 out·1M·98.6% upGoogle AI Studio$2.00 in·$12.00 out·1M·99.8% up
GPT-6 Luna3 hosts
HostInOutContextUptime
Azure AI Foundry$0.10 in·$0.50 out·1.1M·88.4% upOpenAI$0.10 in·$0.50 out·1.1M·99.9% upAmazon Bedrock$0.11 in·$0.55 out·1.1M·99.8% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Gemini 3.1 Pro Preview is developed by Google AI while GPT-6 Luna is developed by OpenAI. Gemini 3.1 Pro Preview has a 1.0M token context window vs GPT-6 Luna's 1.1M. You can compare their actual outputs across 20 challenges on Rival to see how they differ in practice.

It depends on your use case. Gemini 3.1 Pro Preview and GPT-6 Luna each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 20 challenges so you can judge which fits your needs best.

Gemini 3.1 Pro Preview costs $2/M input tokens and GPT-6 Luna costs $0.1/M input tokens. GPT-6 Luna is $1.90/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of Gemini 3.1 Pro Preview and GPT-6 Luna 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 Pro Preview logoSolar Mini 4 logo
Gemini 3.1 Pro Preview vs Solar Mini 4Landed Sep 2026
GPT-6 Luna logoQwen3.8 Max Prime logo
GPT-6 Luna vs Qwen3.8 Max PrimeLanded Sep 2026
Gemini 3.1 Pro Preview logoGLM 5.3 Prime logo
Gemini 3.1 Pro Preview vs GLM 5.3 PrimeLanded Sep 2026
GPT-6 Luna logoQwen3.8 Omni Flash logo
GPT-6 Luna vs Qwen3.8 Omni FlashLanded Sep 2026
Gemini 3.1 Pro Preview logoCommand A+ logo
Gemini 3.1 Pro Preview vs Command A+Landed Sep 2026
GPT-6 Luna logoClaude Opus 5.5 logo
GPT-6 Luna vs Claude Opus 5.5Landed Sep 2026
Gemini 3.1 Pro Preview logoGPT-6 Luna Pro logo
Gemini 3.1 Pro Preview vs GPT-6 Luna ProLanded Sep 2026
GPT-6 Luna logoGPT-6 Sol Pro logo
GPT-6 Luna vs GPT-6 Sol ProLanded Sep 2026

Same lab, same size, long tail

Gemini 3.1 Pro Preview logoGemini 3.1 Flash Lite Preview logo
Gemini 3.1 Pro Preview vs Gemini 3.1 Flash Lite PreviewVersion compare
Gemini 3.1 Pro Preview logoGemini 3.8 Flash logo
Gemini 3.1 Pro Preview vs Gemini 3.8 FlashSame lab
GPT-6 Luna logoGPT-6 Luna Pro logo
GPT-6 Luna vs GPT-6 Luna ProSame lab
GPT-6 Luna logoGPT-6 Sol logo
GPT-6 Luna vs GPT-6 SolSame lab
Gemini 3.1 Pro Preview logoClaude Haiku 4.5 logo
Gemini 3.1 Pro Preview vs Claude Haiku 4.5New provider
GPT-6 Luna logoClaude Opus 4 logo
GPT-6 Luna vs Claude Opus 4New provider
GPT-6 Luna logoClaude Opus 4.1 logo
GPT-6 Luna vs Claude Opus 4.1New provider
Gemini 3.1 Pro Preview logoClaude Opus 4.5 logo
Gemini 3.1 Pro Preview vs Claude Opus 4.5Same size

Model pages

Gemini 3.1 Pro Preview logo
Gemini 3.1 Pro Preview53 outputs, specs and price
GPT-6 Luna logo
GPT-6 Luna20 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
  • 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