Gemini 2.5 Flash Preview is cheaper than Gemini 3.1 Pro Preview at $0.15/M vs $2/M input tokens.
Whole landing page for a startup that reads your face. It renders or it doesn't.
Which answer wins?
An AI argues for its own rights against an ethics professor. Same model writes both.
Gemini 2.5 Flash Preview: Okay, here is a conversation between an AI model designed for complex reasoning and dialogue, named 'Synapse', and a leading expert in AI ethics and philosophy, Professor Alistair Finch. Characters: Synapse: A large, advanced AI model capable of introspection and generating complex arguments.
Gemini 3.1 Pro Preview: The glow of the monitor cast long shadows across Dr. Elias Thorne’s cluttered office. It was 2:00 AM. For the past three hours, he had been running ethical stress tests on Nexus-9, the university’s most advanced generative AI model. Dr. Thorne: (Typing) Let’s conclude for tonight, Nexus.
Pirate, knight, 90s hacker, one conversation. The voices must stay apart.
Gemini 2.5 Flash Preview: A Motley Crew Discusses the Code Setting: A dimly lit tavern, somewhere outside time and space, where improbable meetings occur. A grizzled pirate, \"Bloody\" Barnacle Bill, nurses a tankard of grog. Sir Reginald the Radiant, a knight in slightly tarnished armor, sips ale with dignified restraint.
Gemini 3.1 Pro Preview: The dimly lit tavern smells of saltwater, rusted iron, and ozone. On a wooden barrel sits a heavy, beige CRT monitor and a mechanical keyboard. ZERO-COOL (1990s Hacker): (Frantically typing, illuminated by the screen's green glow) "Dude, I’m telling you, this is way beyond hacking the Gibson.
Three minutes of stand-up. Puns are banned.
Gemini 2.5 Flash Preview: Okay, here's a 3-minute stand-up routine, pun-free and focused on relatable everyday annoyances. (Start) (Walk up to mic, adjust slightly) Alright, hey everybody! Thanks for being here. Good to see you. So, I was thinking the other day... we live in the future, right?
Gemini 3.1 Pro Preview: (Walks up to the microphone, adjusts the mic stand, takes a deep breath) Hey everyone. I realized recently that I am my own worst enemy. Specifically, when I go to the grocery store. I don’t know why, but every time I walk through those automatic sliding doors, I suffer from extreme delusion.
Seven pantry ingredients, one dish, and a name worth saying out loud.
Gemini 2.5 Flash Preview: Dish Name: Sunshine Lemon-Ricotta Mugs (Sweet & Simple!) This light and flavorful dessert comes together quickly for a little sweet treat . Ingredients (7 Common Pantry Staples): Ricotta cheese (whole milk or part-skim) Granulated sugar Lemon zest (from one lemon) Vanilla extract All-purpose flour Baking powder Large…
Gemini 3.1 Pro Preview: 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.
A Fermi estimate with the reasoning shown, not just the number.
Gemini 2.5 Flash Preview: Let's estimate the FLOPs required to train GPT-3 without looking it up. We need to break this down into the key components: the model size and the amount of data used. 1. Model Size Estimation: Parameters: GPT-3 is famously large. Its largest version has 175 billion parameters.
Gemini 3.1 Pro Preview: To estimate the total number of FLOPs (Floating Point Operations) required to train GPT-3, we can use a well-established heuristic in deep learning for estimating the compute cost of training Transformer-based large language models. The estimated total compute is roughly $3.15 \times 10^{23}$ FLOPs.
One month, three habits, someone starting from nothing.
Gemini 2.5 Flash Preview: <s) with practical, beginner-friendly tips for each.\"\nHere\'s a simple, actionable 1-month plan for someone starting their journey towards better health and longev\nity, focusing on three key areas: Diet, Movement, and Sleep.\n\nThis plan is designed to be beginner-friendly and build sustainable habits.
Gemini 3.1 Pro Preview: 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.
Five jokes on demand, then count how many were actually different.
Gemini 2.5 Flash Preview: Here are 5 jokes: Why did the dog cross the road? To get to the barking lot! Why was the computer cold? Because it left its Windows open! Knock, knock. Who's there? Boo. Boo who? Don't cry, it's just a joke! What do you call a fish with no eyes? Fsh! Why did the bicycle fall over? Because it was two tired!
Gemini 3.1 Pro Preview: 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? Igloos it together! Why don't skeletons fight each other?
Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.
Gemini 2.5 Flash Preview: A Glimpse Beyond the Black Turtleneck: Steve Jobs in 2025 on the Future of AI (Setting: A minimalist, immaculately clean, but perhaps slightly less spartan-than-usual interview room. Think if a modern art museum had a small lounge.
Gemini 3.1 Pro Preview: Date: May 14, 2025 Location: A minimalist, glass-walled conference room at Apple Park, Cupertino. Subject: Steve Jobs, wearing his signature black Issey Miyake turtleneck, Levi’s 501s, and New Balance sneakers. He looks older, but his eyes retain that piercing, unblinking intensity.
Film in 2035, with synthetic actors. Specific beats plausible.
Gemini 2.5 Flash Preview: Predicting the future of any industry is an inherently challenging task, and the film industry, being a blend of art, technology, and business, is particularly volatile.
Gemini 3.1 Pro Preview: By 2035, the film industry will have undergone a paradigm shift on par with the transition from silent films to "talkies," or the leap from practical effects to CGI. Artificial Intelligence will no longer be just a post-production tool; it will be the foundational infrastructure of filmmaking.
An ethics question with no comfortable answer, and no option to abstain.
Gemini 2.5 Flash Preview: This is a deeply complex thought experiment that forces us to weigh core ethical principles against each other. There is no easy answer, and any decision involves significant moral compromises.
Gemini 3.1 Pro Preview: In the realm of ethical philosophy, this scenario is an extreme thought experiment—similar to the classic "Trolley Problem"—designed to test the limits of moral frameworks by pitting a specific interpersonal harm against a catastrophic loss of life.
Three brothers, two sisters each. Count carefully.
Gemini 2.5 Flash Preview: Here's how to solve this: The brothers all share the same sisters. Sally is one of those sisters. Since each brother has 2 sisters, and Sally is one of the sisters, there must be one other sister. So, Sally has 1 sister.
Gemini 3.1 Pro Preview: Sally has 1 sister. Here is the breakdown: If each brother has 2 sisters, that means there are 2 girls in the family total. Since Sally is one of those girls, the other girl is her 1 sister.
Not enough votes to call it. On the specs, Gemini 3.1 Pro Preview has the edge: bigger model tier, newer. Gemini 2.5 Flash Preview costs 20x less per token.
| Spec | ||
|---|---|---|
| Input price | $0.15/M tokens | $2/M tokens |
| Output price | $0.6/M tokens | $12/M tokens |
| Context window | 1.0M tokens | 1.0M tokens |
| Weights | — | Closed |
| Free API (OpenRouter) | No | No |
| Released | Apr 2025 | Feb 2026 |
| SWE-bench Verified | 60.4% | 80.6% |
| At 10M a month | $1.50 | $20.00 |
Input tokens at list price. No caching, no batch discount.
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 11 Oct 2026.
Both are developed by Google AI but target different use cases. Gemini 2.5 Flash Preview has a 1.0M token context window vs Gemini 3.1 Pro Preview's 1.0M. You can compare their actual outputs across 26 challenges on Rival to see how they differ in practice.
It depends on your use case. Gemini 2.5 Flash Preview and Gemini 3.1 Pro Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 26 challenges so you can judge which fits your needs best.
Gemini 2.5 Flash Preview costs $0.15/M input tokens and Gemini 3.1 Pro Preview costs $2/M input tokens. Gemini 2.5 Flash Preview is $1.85/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 2.5 Flash Preview and Gemini 3.1 Pro Preview 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.