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  5. GPT-4vsMercury 2.5 Preview
Updated Aug 2026

GPT-4vsMercury 2.5 Preview

Mercury 2.5 Preview is cheaper than GPT-4 at $0.04/M vs $30/M input tokens.

GPT-4 and Mercury 2.5 Preview compared across 26 shared prompts
SpecGPT-4Mercury 2.5 Preview
Input price$30/M tokens$0.04/M tokens
Output price$60/M tokens$0.15/M tokens
Context window8K tokens260K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedMay 2023Aug 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 26 prompts both answered. Formatting stripped, words untouched.

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…

GPT-4442 words
Day 1: 8 AM-10 AM: Convene an emergency meeting with your core leadership team. This team includes the heads of Legal, Regulatory Affairs, Medical, Research and Development, Finance, and Communications. Brief them on the situation and ask for their initial input and strategies for managing the situation.
Read the full answer
Mercury 2.5 Preview709 words
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).
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…

GPT-4375 words
Title: 1-Month Plan for Better Health and Longevity Week 1 - Establishing a Healthy Diet 1.1: Start Eating Whole Foods: Begin by gradually replacing processed foods in your diet with whole foods. This may include fruits, vegetables, lean proteins, and whole grains.
Read the full answer
Mercury 2.5 Preview176 words
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.
Read the full answer

Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

GPT-4495 words
Experienced Software Engineer: How does a language model like GPT produce intelligent behavior? Think of it as a highly specialized function in your code. This function has been trained on a large amount of text data, and it's main goal is to predict the next word in a sentence given the previous words.
Read the full answer
Mercury 2.5 Preview608 words
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.
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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…

GPT-4441 words
An early invention of the transistor in 1920 would have had profound implications across numerous domains, drastically altering the course of history. Technological Implications: WWII: The transistor, a fundamental component of modern electronic devices, could have advanced the technology used in WWII significantly.
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Mercury 2.5 Preview683 words
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.
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Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

GPT-4533 words
SCOPE: The lack of specificity can be used against the contractor in that the client can modify the scope of work at will without renegotiating the price. This could lead to the contractor working beyond the initially agreed upon parameters without additional pay.
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Mercury 2.5 Preview500 words
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.
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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.…

GPT-4298 words
Weak Claim 1 - Solution: While the claim that the proprietary EEG headband uses advanced ML to decode neural patterns into text with 94% accuracy is impressive, it doesn't address concerns about user comfort, ease of use, or aesthetics.
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Mercury 2.5 Preview312 words
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."
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Our Verdict
GPT-4
GPT-4
Mercury 2.5 Preview
Mercury 2.5 Preview

Not enough votes to call it. On the specs, nothing separates them.

Mercury 2.5 Preview costs 400x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-4
Input
$30.00
Output
$60.00
Mercury 2.5 Preview
Input
$0.04
750× cheaper
Output
$0.15
400× cheaper

Mercury 2.5 Preview is cheaper on both: 750× input, 400× output.

Where to run it

3 hosts

GPT-42 hosts
HostInOutContextUptime
Azure AI Foundry$30.00 in·$60.00 out·8k·100% upOpenAI$30.00 in·$60.00 out·8k·99.8% up
Mercury 2.5 Preview1 host
HostInOutContextUptime
Inception$0.04 in·$0.15 out·260k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Writing DNA

Style Comparison

Similarity
55%

Mercury 2.5 Preview uses 78.7x more headings

GPT-4
Mercury 2.5 Preview
59%Vocabulary65%
18wSentence Length14w
1.10Hedging0.44
0.8Bold4.9
2.5Lists3.3
0.00Emoji0.00
0.00Headings0.79
0.45Transitions0.20
Based on 15 + 26 text responses
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Rival
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