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  5. Gemini 3.1 Flash Lite PreviewvsGPT-6 Luna Pro
Updated Sep 2026

Gemini 3.1 Flash Lite PreviewvsGPT-6 Luna Pro

GPT-6 Luna Pro is cheaper than Gemini 3.1 Flash Lite Preview at $0.1/M vs $0.25/M input tokens.

Gemini 3.1 Flash Lite Preview and GPT-6 Luna Pro compared across 20 shared prompts
SpecGemini 3.1 Flash Lite PreviewGPT-6 Luna Pro
Input price$0.25/M tokens$0.1/M tokens
Output price$1.5/M tokens$0.5/M tokens
Context window1.0M tokens1.1M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedMar 2026Sep 2026
Side by side

Same prompt, both answers

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

Michelin Star Recipe Design

Design an innovative recipe for a multi-component dish worthy of a Michelin 3-star restaurant. The recipe should feature an unusual…

Gemini 3.1 Flash Lite Preview568 words
The Dish: "Nebula of the Forest Floor" Conceptual Narrative: This dish explores the intersection of decay and rebirth. The pairing—Black Garlic and Wild Foraged Pine Needles—creates an umami-forward, resinous profile that mimics the damp, dark scent of an ancient coniferous forest.
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GPT-6 Luna Pro1,215 words
Turbot, Sea Buckthorn, Mussel Beurre Blanc, and Celery-Root Silk Serves 4 A composed main course built around an unusual but harmonious pairing: briny mussel and turbot with intensely tart, apricot-like sea buckthorn.
Read the full answer

Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

Gemini 3.1 Flash Lite Preview657 words
This architecture contains several critical flaws that would lead to data loss, inconsistent state, and poor user experience in a real-time environment. The "Split-Brain" Broadcast Problem Issue: The architecture only broadcasts changes to clients connected to the same server.
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GPT-6 Luna Pro1,906 words
The main architectural risk is that this design treats collaborative editing as ordinary “last write wins” data storage. It is not: edits need a well-defined order, reliable propagation, and a conflict model that preserves concurrent work.
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 Flash Lite Preview524 words
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.
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GPT-6 Luna Pro327 words
A simple 1-month plan for better health and longevity Choose three foundations: eating well, moving regularly, and sleeping consistently. Aim for steady habits, not perfection. Diet: Make nourishing choices easier Week 1: Add one serving of fruit or vegetables to one meal each day.
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Startup Pitch Teardown

Here's a pitch deck summary for a startup called "MindMeld AI": **Slide 1 - Vision:** "We're building the future of human-AI collaboration.…

Gemini 3.1 Flash Lite Preview540 words
To improve the "MindMeld AI" pitch, you must address the gap between "science fiction" and "viable product." Here are the three weakest claims and how to strengthen them. The Claim: "Predict what you want to type before you think it." Why it’s weak: Scientifically, this borders on pseudoscience.
Read the full answer
GPT-6 Luna Pro401 words
“94% accuracy” and “works with any language, any device” Why it’s weak: “Accuracy” is undefined. It could mean classifying a small set of prompted words in a controlled lab—not reliably generating free-form text.
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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 Lite Preview365 words
Financial Projections (FY2026–FY2030) Initial Setup (End of FY2025): EV: $120m * 12.0x = $1,440m Fees: $1,440m * 2.0% = $28.8m Term Loan (4.0x): $480m Mezzanine (1.5x): $180m Equity: $1,440m + $28.8m - $480m - $180m = $808.8m Metric ($m) FY2026 FY2027 FY2028 FY2029 FY2030 Revenue 972.0 1,040.0 1,102.4 1,157.5 1,215.4…
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GPT-6 Luna Pro434 words
Operating and debt schedule Conventions: Interest is calculated on beginning-of-year debt; the 1% Term Loan amortization is 1% of its original $480m principal ($4.8m annually). Mezzanine PIK accrues at 2% annually.
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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 Flash Lite Preview751 words
If the transistor had been invented in 1920, the trajectory of the 20th century would have shifted from the "Mechanical/Vacuum Age" to the "Information Age" two decades before the start of World War II. Here is a trace of the implications through 1980.
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GPT-6 Luna Pro1,661 words
The biggest change would not be that 1920 suddenly gets modern computers. It would be that governments and firms have six or seven extra decades to develop semiconductor materials, manufacturing, and applications.
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Our Verdict
GPT-6 Luna Pro
GPT-6 Luna Pro
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite PreviewRunner-up

Not enough votes to call it. On the specs, GPT-6 Luna Pro has the edge: bigger model tier, newer.

GPT-6 Luna Pro costs 3.0x 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 Flash Lite Preview
Input
$0.25
Output
$1.50
GPT-6 Luna Pro
Input
$0.10
2.5× cheaper
Output
$0.50
3.0× cheaper

GPT-6 Luna Pro is cheaper on both: 2.5× input, 3.0× output.

Where to run it

3 hosts

Gemini 3.1 Flash Lite Preview1 host
HostInOutContextUptime
Google AI Studio$0.25 in·$1.50 out·1M·99.7% up
GPT-6 Luna Pro2 hosts
HostInOutContextUptime
Azure AI Foundry$0.10 in·$0.50 out·1.1M·98.6% upOpenAI$0.10 in·$0.50 out·1.1M·99.9% 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 Flash Lite Preview is developed by Google AI while GPT-6 Luna Pro is developed by OpenAI. Gemini 3.1 Flash Lite Preview has a 1.0M token context window vs GPT-6 Luna Pro'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 Flash Lite Preview and GPT-6 Luna Pro 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 Flash Lite Preview costs $0.25/M input tokens and GPT-6 Luna Pro costs $0.1/M input tokens. GPT-6 Luna Pro is $0.15/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 Flash Lite Preview and GPT-6 Luna Pro 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

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Same lab, same size, long tail

Gemini 3.1 Flash Lite Preview logoGemini 3.1 Pro Preview logo
Gemini 3.1 Flash Lite Preview vs Gemini 3.1 Pro PreviewVersion compare
Gemini 3.1 Flash Lite Preview logoGemini 3.8 Flash logo
Gemini 3.1 Flash Lite Preview vs Gemini 3.8 FlashSame lab
GPT-6 Luna Pro logoGPT-6 Sol Pro logo
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GPT-6 Luna Pro logoGPT-6 Sol logo
GPT-6 Luna Pro vs GPT-6 SolSame lab
Gemini 3.1 Flash Lite Preview logoClaude 3.7 Sonnet logo
Gemini 3.1 Flash Lite Preview vs Claude 3.7 SonnetNew provider
Gemini 3.1 Flash Lite Preview logoClaude 3.7 Thinking Sonnet logo
Gemini 3.1 Flash Lite Preview vs Claude 3.7 Thinking SonnetNew provider
Gemini 3.1 Flash Lite Preview logoClaude Sonnet 4.5 logo
Gemini 3.1 Flash Lite Preview vs Claude Sonnet 4.5New provider
Gemini 3.1 Flash Lite Preview logoClaude Fable 5 logo
Gemini 3.1 Flash Lite Preview vs Claude Fable 5New provider

Model pages

Gemini 3.1 Flash Lite Preview logo
Gemini 3.1 Flash Lite Preview53 outputs, specs and price
GPT-6 Luna Pro logo
GPT-6 Luna Pro20 outputs, specs and price
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