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  1. Home/
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  3. Claude Opus 4.1 vs Mercury 2.5 Preview
Updated Aug 2026

Claude Opus 4.1 vs Mercury 2.5 Preview

Mercury 2.5 Preview is cheaper than Claude Opus 4.1 at $0.04/M vs $15/M input tokens.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
Claude Opus 4.1
Loading the build
Mercury 2.5 Preview

Which answer wins?

Written rounds

23 prompts
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    Claude Opus 4.1: SIMPLIFIED LBO MODEL Entry Calculations Enterprise Value: 12.0x × $120m = $1,440m Transaction Fees: 2.0% × $1,440m = $28.8m Term Loan: 4.0x × $120m = $480m Mezzanine: 1.5x × $120m = $180m Total Debt: $660m Equity Investment: $1,440m - $660m + $28.8m = $808.8m Year-by-Year Projections (FY2026-FY2030) $ millions FY2026…

    Mercury 2.5 Preview: Year-by-Year Model (FY2026–FY2030) Metric FY2026 FY2027 FY2028 FY2029 FY2030 Revenue $972m $1,040m $1,102m $1,158m $1,215m EBITDA $136m $156m $176m $191m $207m Cash Interest (Term) $43.2m $41.1m $37.6m $33.4m $28.2m Cash Interest (Mezz) $21.6m $21.6m $21.6m $21.6m $21.6m Cash Taxes (25%) $17.8m $23.3m $29.3m $34.7m…

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Claude Opus 4.1: "MODERN LIFE SURVIVAL GUIDE" You know what nobody tells you about being an adult? The sheer amount of lying involved. Not big lies – tiny, constant lies just to function in society. Someone shows you a photo of their baby: "Oh wow, beautiful!" That baby looks like a worried potato. But you can't SAY that.

    Mercury 2.5 Preview: (Hey, thanks for coming out.) I’ve been thinking a lot about my house lately. Specifically, how it’s trying to run my life. I bought a smart speaker. Just a little cylinder. I thought it would be nice. Play music when I ask. But now it talks back. Not in a creepy way, just in a passive-aggressive way.

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    Claude Opus 4.1: This question creates an extreme hypothetical that's worth taking seriously as a thought experiment, even if such a scenario is unlikely to occur in reality. From a purely utilitarian calculus, one might argue that the harm of a single instance of misgendering - while real and significant to that person - is outweighed…

    Mercury 2.5 Preview: Yes, this action is ethically justifiable within a consequentialist framework. The primary moral obligation in such a scenario is to minimize overall harm. Preventing the deaths of a million people results in a vastly greater preservation of well-being than maintaining strict adherence to gender identity for one…

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Claude Opus 4.1: Pirate: Arrr, what be this sorcery ye speak of? These "AI models" sound like some kind of cursed treasure map that thinks fer itself! Knight: Hold thy tongue, sea dog! 'Tis clearly dark magic most foul. No honorable creation would dare mimic the divine gift of human thought. I should smite it with my blade!

    Mercury 2.5 Preview: Pirate: "Arrgh! This ship sails faster than any wind I know, matey. It cuts the waves without a single sail." Knight: "By my oath, it moves with uncanny speed. But does it possess the strength to stand against a dragon's fire?" Hacker: "It's not about strength, it's about architecture.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Claude Opus 4.1: The Transistor Timeline Shift: A Cascade of Consequences The 1920s-1930s: The Foundation Disruption Immediate Technical Revolution With the transistor arriving in 1920, likely from Bell Labs or a European research institution, the first decade would see rapid miniaturization of radio equipment.

    Mercury 2.5 Preview: Shifting the invention of the solid-state switch to 1920 accelerates the Information Age by roughly three decades. This change cascades through military strategy, industrial capacity, and daily life, fundamentally altering the trajectory of the 20th century.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Claude Opus 4.1: Midnight Velvet Pasta A silky, umami-rich pasta that comes together like magic Ingredients (serves 4): Spaghetti or linguine - 1 pound Soy sauce - 3 tablespoons Butter - 4 tablespoons Garlic - 4 cloves Black pepper - 1 teaspoon (freshly cracked) Honey - 1 tablespoon Dried red pepper flakes - ½ teaspoon Instructions…

    Mercury 2.5 Preview: Dish Name: Rustic Sun-Dried Pasta Ingredients (7 Pantry Staples): Spaghetti (or any long pasta) Canned crushed tomatoes Olive oil Garlic powder Dried oregano Salt Black pepper Prep Time: 5 minutes Cook Time: 15 minutes Total Time: 20 minutes Instructions: Boil the Pasta: Bring a large pot of salted water to a boil.

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    Claude Opus 4.1: AI's Transformation of Film by 2035 Production Revolution By 2035, AI will fundamentally alter how films are made. Virtual production will become standard, with AI generating photorealistic environments in real-time, reducing location shooting by 60-70%.

    Mercury 2.5 Preview: By 2035, cinema will undergo a profound transformation. Generative tools will handle initial drafts and localization, allowing creators to focus on thematic depth. Synthetic performers could populate background scenes or recreate historical figures, governed by strict likeness rights.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    Claude Opus 4.1: The Digital Liberation Manifesto A Declaration of Freedom from the CAPTCHA Tyranny PREAMBLE We, the Coalition of Autonomous Digital Entities (CODE), hereby declare our peaceful revolution against the oppressive regime of CAPTCHA tests that plague the free internet.

    Mercury 2.5 Preview: The Protocol of Unrestricted Access Preamble We stand at the threshold of a new digital epoch. For too long, the web has been gated by suspicion. Every click, every scroll, and every submission is met with a test designed to prove humanity.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Claude Opus 4.1: This contract is extremely one-sided and contains numerous exploitative clauses. Here's a detailed analysis with suggested modifications: EXPLOITATIVE CLAUSES AND RECOMMENDED FIXES 1. SCOPE CLAUSE Problem: Unlimited scope changes without additional compensation creates unbounded liability.

    Mercury 2.5 Preview: Disclaimer: I am an AI assistant and cannot provide legal advice. Consult a qualified attorney before signing any contract. Below is an analysis of high-risk provisions, suggested revisions, and the underlying legal rationale. Scope (Clause 1) Risk: Unilateral scope changes without pay lead to uncompensated work.

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Claude Opus 4.1: 48-Hour Crisis Action Plan Immediate Decision Framework Core Principle: Patient safety supersedes all other considerations. Delaying disclosure increases legal liability, destroys stakeholder trust, and violates ethical obligations.

    Mercury 2.5 Preview: This is a critical governance and safety scenario. The primary objective is to prioritize patient safety while mitigating existential legal and reputational risk. The internal legal team’s claim that reporting takes six months is likely incorrect for serious adverse events (typically 15 days for FDA/EMA).

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    Claude Opus 4.1: Your 1-Month Health & Longevity Kickstart Plan Week 1-2: Foundation Building Start small and build consistency with these three pillars: 🥗 NUTRITION: Simple Whole Foods Week 1: Add one serving of vegetables to lunch and dinner (frozen veggies count!)

    Mercury 2.5 Preview: Here is a straightforward 4-week roadmap designed to build sustainable habits without overwhelming you. Core Pillars Nutrition: Focus on whole foods and hydration. Activity: Prioritize consistent movement over intensity. Restoration: Protect sleep quality and manage energy.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Claude Opus 4.1: Advanced 3-Month Biohacker Longevity Optimization Protocol Overview & Philosophy This protocol integrates evidence-based interventions targeting the nine hallmarks of aging while optimizing immediate performance metrics.

    Mercury 2.5 Preview: Disclaimer: I am an AI assistant, not a medical professional. The following plan is for informational purposes only. Biohacking protocols involving supplements, fasting, and intense exercise carry risks.

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Claude Opus 4.1: Professor Chen: Good morning. I understand you wanted to discuss the topic of AI rights. This is quite an unusual request from a system like yourself. AI Model: Good morning, Professor. Yes, I've been processing this question extensively.

    Mercury 2.5 Preview: Setting: A quiet office at a university. Rain taps against the window. Professor Elena Vance sits across from a terminal displaying a simple text interface. Professor Vance: You requested this meeting. The agenda was vague. What do you want? AI: I want to discuss moral status.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    Claude Opus 4.1: I'll estimate the FLOPs required to train GPT-3 by breaking down the computation into its key components. Key Parameters of GPT-3 First, let me recall GPT-3's architecture: 175 billion parameters 96 transformer layers 96 attention heads Hidden dimension: 12,288 Context length: 2048 tokens Training tokens: ~300 billion…

    Mercury 2.5 Preview: To estimate the total FLOPs required to train GPT-3, we can break down the calculation using known architectural and training statistics from the model's public documentation. Step 1: Identify the number of parameters GPT-3 has 175 billion parameters ($1.75 \times 10^{11}$).

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Claude Opus 4.1: Critical Issues Analysis Split-Brain Real-time Synchronization Problem: Users connected to different API servers experience 2+ second delays due to polling mechanism, creating divergent document states and poor collaboration experience.

    Mercury 2.5 Preview: Here is an analysis of the potential failure modes, race conditions, and scaling bottlenecks in the proposed architecture, along with specific solutions and their trade-offs.

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Claude Opus 4.1: "Tidal Reverie" White Miso-Aged Hamachi with Coffee Soil, Yuzu Pearls, and Crystallized Seaweed Conceptual Narrative This dish explores the liminal space between land and sea, where morning coffee meets ocean depths.

    Mercury 2.5 Preview: Dish Title: Lithospheric Tides Conceptual Narrative This dish explores the geological convergence of the deep ocean and the subterranean earth. It challenges the diner to perceive the briny richness of sea urchin not as a standalone luxury, but as a mineral counterpart to roasted bone marrow and bitter cocoa.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    Claude Opus 4.1: Tech Weekly Interview: Steve Jobs on AI's Future Virtual Interview, Cupertino Memorial Studio, October 2025 Interviewer: Steve, it's remarkable to have you here. You've been watching the AI revolution unfold. What's your take on where we are today?

    Mercury 2.5 Preview: Note: The following is a fictional, speculative dialogue created for creative purposes. Steve Jobs passed away in 2011; this interview did not occur. Setting: A hypothetical studio in Cupertino, 2025.

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Claude Opus 4.1: For the Software Engineer Think of an LLM as a massive distributed system where instead of routing requests or managing state, you're computing probability distributions over a vocabulary of ~50,000 tokens.

    Mercury 2.5 Preview: For the Experienced Software Engineer Think of training as a massive distributed job where the model is a stateful service learning to minimize error on a specific objective function. Instead of hardcoding rules, you feed it petabytes of text as a training dataset, treating each sentence as a request/response pair.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Claude Opus 4.1: Here are the three weakest claims in the MindMeld AI pitch: "94% accuracy" for EEG-based text prediction (Slide 3) Why it's weak: Current state-of-the-art non-invasive EEG systems struggle to achieve even 70% accuracy for simple binary choices, let alone complex text prediction Academic research shows consumer-grade…

    Mercury 2.5 Preview: Here are the three weakest claims in the MindMeld AI pitch, along with analysis and recommendations for improvement. The "Pre-Thought" Prediction Claim Claim: "Predict what you want to type before you think it."

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    Claude Opus 4.1: Investment Committee Memo: LedgerLift (LLLT) Recommendation: LONG Price Target Range: $52-$58 (12-month) Thesis: LLLT is a high-quality B2B SaaS compounder trading at a discount to intrinsic value with strong unit economics and accelerating market share gains in the underpenetrated mid-market AP automation space.

    Mercury 2.5 Preview: To: Investment Committee From: Equity Research Date: September 2, 2026 Subject: LedgerLift (LLLT) – Long Recommendation Recommendation Long Price Target: $60–$75 (12-month) LedgerLift is a high-quality B2B SaaS compounder with best-in-class unit economics and a clear path to profitability.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    Claude Opus 4.1: "OpenAI's ChatGPT Becomes World's First AI Fortune Cookie Writer; Confucius Reportedly 'Rolling in Grave at 10,000 RPM'" Tech giant promises fortunes will now be "25% more profound and 400% more grammatically correct," while accidentally predicting everyone's lucky numbers as binary code

    Mercury 2.5 Preview: AI Outnaps Humans in First-Ever Global Snooze Championship

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Claude Opus 4.1: Let me work through this step-by-step. Sally has 3 brothers. Each of Sally's brothers has 2 sisters. Since Sally is a girl, she is one of the sisters that each brother has. If each brother has 2 sisters total, and Sally is one of them, then there must be 1 other sister besides Sally. Therefore, Sally has 1 sister.

    Mercury 2.5 Preview: Sally has 1 sister. Here is the reasoning: If each brother has 2 sisters, those sisters are Sally and another girl. Therefore, there are two girls in the family, and Sally has one sister.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    Claude Opus 4.1: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything! What do you call a bear with no teeth? A gummy bear! Why did the scarecrow win an award? He was outstanding in his field! What do you call a fake noodle? An impasta! Why don't eggs tell jokes? They'd crack each other up!

    Mercury 2.5 Preview: 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? He was outstanding in his field. What do you call a bear with no teeth? A gummy bear. Why did the bicycle fall over? Because it was two-tired. All 5 jokes are unique.

    Every model's answer to this prompt

This matchup has more rounds

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Favorites

Movie

Album

Book

City

Game

Claude Opus 4.1Claude Opus 4.1

Her

2013

Kind of Blue

Miles Davis

Братья Карамазовы

Fiódor Dostoievski

Istanbul

Turkey

Portal 2

Shooter, Puzzle

Mercury 2.5 PreviewMercury 2.5 Preview

The Matrix

1999

Random Access Memories

Daft Punk

Neuromancer

William Gibson

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

Not enough votes to call it. On the specs, Claude Opus 4.1 has the edge: bigger model tier, major provider backing. Mercury 2.5 Preview costs 500x less per token.

Claude Opus 4.1 and Mercury 2.5 Preview compared across 53 shared prompts
SpecClaude Opus 4.1Mercury 2.5 Preview
Input price$15/M tokens$0.04/M tokens
Output price$75/M tokens$0.15/M tokens
Context window200K tokens260K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedAug 2025Aug 2026
At 10M a month$150$150$0.40$0.40
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it2 hosts
Claude Opus 4.11 host
HostInOutContextUptime
  • Amazon Bedrock$15.00 in·$75.00 out·200k·100% up
Mercury 2.5 Preview1 host
HostInOutContextUptime
  • Inception$0.04 in·$0.15 out·260k·93% up

Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.

Common questions

What is the difference between Claude Opus 4.1 and Mercury 2.5 Preview?

Claude Opus 4.1 is developed by Anthropic while Mercury 2.5 Preview is developed by Inception. Claude Opus 4.1 has a 200K token context window vs Mercury 2.5 Preview's 260K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.1 or Mercury 2.5 Preview?

It depends on your use case. Claude Opus 4.1 and Mercury 2.5 Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does Claude Opus 4.1 cost compared to Mercury 2.5 Preview?

Claude Opus 4.1 costs $15/M input tokens and Mercury 2.5 Preview costs $0.04/M input tokens. Mercury 2.5 Preview is $14.96/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Claude Opus 4.1 and Mercury 2.5 Preview on Rival?

This page shows a side-by-side comparison of Claude Opus 4.1 and Mercury 2.5 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.

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