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

Gemini 3.1 Flash LitevsGPT-6 Luna Pro

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

Gemini 3.1 Flash Lite and GPT-6 Luna Pro compared across 20 shared prompts
SpecGemini 3.1 Flash LiteGPT-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
ReleasedMay 2026Sep 2026
Side by side

Same prompt, both answers

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

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 Flash Lite323 words
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.
Read the full answer
GPT-6 Luna Pro127 words
Golden Pantry Pancakes Fluffy, lightly sweet pancakes made with everyday staples. Makes: About 6 small pancakes Prep time: 5 minutes Cook time: 10 minutes Ingredients 1 cup all-purpose flour 1 cup milk 1 egg 2 tablespoons sugar 1 teaspoon baking powder ¼ teaspoon salt 2 tablespoons butter, melted (plus a little for the…
Read the full answer

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 Lite557 words
The Dish: "The Forest Floor & The Deep Tide" Concept: This dish explores the juxtaposition of two disparate ecosystems: the subterranean richness of an ancient forest and the brine-heavy, mineral complexity of the deep ocean.
Read the full answer
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

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 Lite521 words
This pitch deck shows a high-potential "moonshot" technology, but it suffers from significant credibility gaps typical of early-stage deep-tech startups. Here are the three weakest claims and how to fix them. The Claim: "Predict what you want to type before you think it."
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.
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 Lite501 words
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.
Read the full answer
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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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 Lite768 words
If the transistor had been invented in 1920—likely by researchers at Bell Labs or a similar entity—the "Electronic Age" would have arrived twenty-seven years earlier. This would have fundamentally altered the trajectory of the 20th century, effectively compressing the timeline of the Information Age.
Read the full answer
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.
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…
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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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Our Verdict
GPT-6 Luna Pro
GPT-6 Luna Pro
Gemini 3.1 Flash Lite
Gemini 3.1 Flash LiteRunner-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
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

4 hosts, cheapest first

Gemini 3.1 Flash Lite2 hosts
HostInOutContextUptime
Google Vertex AI$0.13 in·$0.75 out·1M·99.7% upGoogle AI Studio$0.25 in·$1.50 out·1M·99.9% 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 is developed by Google AI while GPT-6 Luna Pro is developed by OpenAI. Gemini 3.1 Flash Lite 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 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 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 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.

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Same lab, same size, long tail

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GPT-6 Luna Pro logoGPT-6 Sol Pro logo
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GPT-6 Luna Pro logoGPT-6 Sol logo
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GPT-6 Luna Pro logoGemini 3 Flash Preview logo
GPT-6 Luna Pro vs Gemini 3 Flash PreviewSame size
GPT-6 Luna Pro logoGemini 3 Pro Preview logo
GPT-6 Luna Pro vs Gemini 3 Pro PreviewCross-provider
GPT-6 Luna Pro logoGemini 3.1 Flash Lite Preview logo
GPT-6 Luna Pro vs Gemini 3.1 Flash Lite PreviewCross-provider
GPT-6 Luna Pro logoGemini 3.1 Pro Preview logo
GPT-6 Luna Pro vs Gemini 3.1 Pro PreviewCross-provider

Model pages

Gemini 3.1 Flash Lite logo
Gemini 3.1 Flash Lite58 outputs, specs and price
GPT-6 Luna Pro logo
GPT-6 Luna Pro20 outputs, specs and price
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