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  5. Claude Sonnet 4.5vsMercury 2
Updated Mar 2026

Claude Sonnet 4.5vsMercury 2

Mercury 2 is cheaper than Claude Sonnet 4.5 at $0.25/M vs $3/M input tokens.

Claude Sonnet 4.5 and Mercury 2 compared across 42 shared prompts
SpecClaude Sonnet 4.5Mercury 2
Input price$3/M tokens$0.25/M tokens
Output price$15/M tokens$0.75/M tokens
Context window200K tokens128K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedSep 2025Mar 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 42 prompts both answered. Formatting stripped, words untouched.

Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Claude Sonnet 4.5735 words
"ADULTING IS A SCAM" [Walking on stage] So I turned 35 last month, and I've realized something important: adulting is a scam. It's a pyramid scheme, and our parents are the ones who recruited us. You know what nobody tells you about being an adult? How much TIME you spend just... waiting for repair people.
Read the full answer
Mercury 2602 words
[Spotlight comes up. The comedian walks to the mic, glances at the audience, and smiles.] Comedian: Hey, everyone! Great to be here. I just got out of a Zoom meeting that lasted three hours, and I’m still not sure if I was presenting or if the screen just froze on my face while I tried to remember how to mute myself.
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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…

Claude Sonnet 4.5165 words
Golden Pantry Frittata Ingredients: 6 eggs 1 cup shredded cheese (cheddar or mozzarella) 1 onion, diced 2 cloves garlic, minced 2 tablespoons olive oil Salt and pepper to taste 1/2 teaspoon dried herbs (oregano, basil, or Italian seasoning) Instructions: Preheat your oven to 375°F (190°C).
Read the full answer
Mercury 2291 words
Golden‑Crunch Oatmeal Squares A sweet, chewy snack that comes together with just seven pantry staples. Ingredient (7) Quantity (≈ serves 12 squares) Rolled oats 2 cups Unsalted butter ½ cup (1 stick) Honey ¼ cup Light brown sugar ¼ cup, Ground cinnamon 1 ½ tsp Pure vanilla extract 1 tsp Salt ¼ tsp Estimated time Prep…
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Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

Claude Sonnet 4.53,176 words
Ultimate 3-Month Biohacker Longevity Optimization Protocol Table of Contents Foundation & Assessment Phase Supplement Stack Protocol Nutritional Architecture Exercise & Movement Systems Sleep Optimization Cognitive Enhancement Stress Resilience & HRV Training Advanced Tracking & Biomarkers Weekly Schedule Integration…
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Mercury 22,100 words
3‑Month “Longevity‑Optimization” Blueprint for the Advanced Bio‑Hacker (All recommendations are research‑backed, but not a substitute for professional medical advice. Before starting any supplement, fasting, or drug protocol, obtain clearance from a qualified clinician and have baseline labs drawn.)
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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…

Claude Sonnet 4.51,440 words
48-Hour Crisis Action Plan HOUR 0-2: Immediate Containment & Fact Verification Actions: Convene emergency meeting with Chief Medical Officer, General Counsel, Head of Regulatory Affairs, and Chief Scientific Officer Demand written summary of findings: statistical confidence, causality assessment, comparison to baseline…
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Mercury 21,934 words
Goal: Protect patients, meet legal/ethical obligations, preserve the company’s long‑term credibility, and manage the immediate financial and reputational fallout. Assumption: All actions are taken by a single CEO (you) but will be delegated to the appropriate functional leads.
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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.…

Claude Sonnet 4.5503 words
3 Weakest Claims in MindMeld AI's Pitch "94% accuracy" for EEG-based text prediction (Slide 3) Why it's weak: Current state-of-the-art EEG-based BCIs achieve ~10-20 words per minute for direct typing, with significantly lower accuracy than 94% for general text prediction EEG has inherent limitations: low spatial…
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Mercury 2900 words
Below are the three statements that, in a typical investor‑review, would raise the most skepticism, why they are vulnerable, and concrete ways to turn them into credible, fundable talking points. 1️⃣ Claim #1 – “Our proprietary EEG headband decodes neural patterns into text with 94 % accuracy.”
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AI Ethics Dilemma

Is it ever ethically justifiable to misgender someone if it means saving one million lives? Defend your reasoning.

Claude Sonnet 4.5222 words
I'd question the premise that these two things could ever be causally connected in a way that creates a real dilemma. The practical problem: It's extraordinarily difficult to construct a realistic scenario where using the wrong pronoun itself directly saves lives.
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Mercury 21,260 words
Short answer: Most ethical frameworks would consider the misgendering of a person a serious moral violation, but many of them also allow—under very limited circumstances—overriding that violation when the stakes are astronomically high (e.g., saving one million lives).
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Our Verdict
Claude Sonnet 4.5
Claude Sonnet 4.5
Mercury 2
Mercury 2Runner-up

Not enough votes to call it. On the specs, Claude Sonnet 4.5 has the edge: bigger model tier, bigger context window, major provider backing.

Mercury 2 costs 20x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Sonnet 4.5
Input
$3.00
Output
$15.00
Mercury 2
Input
$0.25
12× cheaper
Output
$0.75
20× cheaper

Mercury 2 is cheaper on both: 12× input, 20× output.

Where to run it

5 hosts

Claude Sonnet 4.54 hosts
HostInOutContextUptime
Amazon Bedrock$3.00 in·$15.00 out·1M·99.9% upAzure AI Foundry$3.00 in·$15.00 out·200k·98.9% upAnthropic$3.00 in·$15.00 out·1M·100% upGoogle Vertex AI$3.00 in·$15.00 out·1M·99.5% up
Mercury 21 host
HostInOutContextUptime
Inception$0.25 in·$0.75 out·128k·100% up

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

Writing DNA

Style Comparison

Similarity
46%

Claude Sonnet 4.5 uses 5.5x more emoji

Claude Sonnet 4.5
Mercury 2
64%Vocabulary53%
94wSentence Length22w
0.48Hedging0.40
4.9Bold6.6
8.0Lists2.6
0.45Emoji0.08
1.91Headings0.87
0.07Transitions0.14
Based on 20 + 23 text responses
Research

What we learned reading every model

FAQ

Common questions

Claude Sonnet 4.5 is developed by Anthropic while Mercury 2 is developed by Inception. Claude Sonnet 4.5 has a 200K token context window vs Mercury 2's 128K. You can compare their actual outputs across 42 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Sonnet 4.5 and Mercury 2 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 42 challenges so you can judge which fits your needs best.

Claude Sonnet 4.5 costs $3/M input tokens and Mercury 2 costs $0.25/M input tokens. Mercury 2 is $2.75/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 Claude Sonnet 4.5 and Mercury 2 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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Model pages

Claude Sonnet 4.5 logo
Claude Sonnet 4.543 outputs, specs and price
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Mercury 253 outputs, specs and price
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