Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare models
  • All models
  • Image comparison
  • Audio comparison
  • Image generation
  • Best AI for...
  • Arena
  • API pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model updates
  • Provider status
  • AI creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy policy
  • Terms
  • RSS feed
  1. Home/
  2. Compare/
  3. GPT-5.4 vs Mercury 2
Updated Mar 2026

GPT-5.4 vs Mercury 2

Mercury 2 is cheaper than GPT-5.4 at $0.25/M vs $2.5/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
GPT-5.4
Loading the build
Mercury 2

Which answer wins?

Written rounds

23 prompts
  • Three minutes of stand-up. Puns are banned.

    GPT-5.4: Absolutely — here’s a tight, conversational 3-minute stand-up routine with no pun-based humor: I’ve reached the age where going out requires a staff meeting with myself. Not even a real event. Somebody texts, “Hey, want to grab drinks Friday?” and suddenly I’m in negotiations like I’m representing a small country.

    Mercury 2: [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.

    Every model's answer to this prompt
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    GPT-5.4: Below is a simplified 5-year LBO model for HarborTech Services (HTS) using only the assumptions provided. Entry, sources & uses Purchase price FY2025 EBITDA = $120.0m Entry multiple = 12.0x Enterprise Value = 12.0 × 120.0 = $1,440.0m Fees Transaction fees = 2.0% of EV = 2.0% × 1,440.0 = $28.8m Uses Purchase of…

    Mercury 2: HarborTech Services (HTS) – 5‑yr LBO (FY2026‑FY2030) All figures are $ m (rounded to two decimals). FY Revenue EBITDA Term‑Loan Int. (9%) Mezz Int. (12%) Total Int. Cash Tax (25% of EBITDA‑Int.) Capex (3% Rev) ΔNWC (0.5% ΔRev) Required Amort. (4.8) Free Cash Flow (EBITDA‑Int‑Tax‑Capex‑ΔNWC‑Amort.)

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

    GPT-5.4: Below is a high-level, educational 12-week framework for “longevity-oriented performance optimization.” It is not medical advice and shouldn’t replace care from a physician, especially because some interventions biohackers use can interact with medications, affect liver/kidney function, sleep, mood, blood pressure…

    Mercury 2: 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.)

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

    GPT-5.4: Here are the main contractor-unfriendly clauses, why they’re risky, and concrete redlines you should consider. This is business/legal information, not legal advice; for an actual engagement, a lawyer in the relevant jurisdiction should review it.

    Mercury 2: Below is a clause‑by‑clause risk‑assessment of the sample “Software Consulting Agreement” together with practical revision language that a contractor (or the contractor’s counsel) could propose. The analysis is framed as general information about typical U.S.

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

    GPT-5.4: Pirate: Arrr, so these AI models be like clever parrots, aye? They learn from heaps o’ words and then squawk back what fits best. Knight: Verily, a fine comparison. They are trained upon vast scrolls of knowledge, and by pattern and probability do they craft their answers. Hacker: Yeah, basically.

    Mercury 2: Pirate: Arr, ye scurvy coders! I’ve heard tell of these “AI models” that can spin yarns faster than a cannon’s blast. What be this sorcery, matey? Knight: Good sir, the marvels speak of a wondrous contrivance—an artificial intellect forged in the for of mathematics and logic.

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

    GPT-5.4: Creative Name: Golden Crunch Honey Garlic Noodles 7 Pantry Ingredients: Spaghetti or any noodles Garlic Soy sauce Honey Olive oil Red pepper flakes Breadcrumbs Estimated Time: Prep: 5 minutes Cook: 12 minutes Total: 17 minutes Instructions: Cook the noodles according to package directions.

    Mercury 2: 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…

    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.

    GPT-5.4: I would act as if this will become public soon, because ethically and practically that is the safest assumption. The core principle: patient safety first, evidence preserved, regulators informed promptly, and no misleading statements to investors or physicians.

    Mercury 2: 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.

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

    GPT-5.4: Here are the 3 weakest claims in the deck, with why they’re weak and how to improve them. “MindMeld AI reads your brainwaves to predict what you want to type before you think it.” Why this is weak This is the weakest claim because it sounds scientifically incoherent and overhyped.

    Mercury 2: 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.”

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

    GPT-5.4: I told my computer I needed a break, and now it won’t stop sending me KitKat ads. Why don’t skeletons fight each other? They don’t have the guts. I’m reading a book on anti-gravity. It’s impossible to put down. I used to play piano by ear, but now I use my hands. Why did the scarecrow win an award?

    Mercury 2: Here are five jokes, each with a different punchline: 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. How does a penguin build its house? Igloos it together.

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

    GPT-5.4: LedgerLift (LLLT) — Internal IC Memo Recommendation: Long Current Price: $46 12-month PT range: $58–$74 (base-centered fair value ~$66; downside ~$47; upside ~$86 on DCF, but we cap 12-month bull PT at $74 to reflect execution/rating risk) Two-sentence thesis: LedgerLift screens as a high-quality vertical SaaS/fintech…

    Mercury 2: Internal Investment Committee Memo – LedgerLift (LLLT) Date: 5 Mar 2026 Recommendation Rating: Long 12‑month price target range: $35 – $55 (mid‑point ≈ $45) Thesis (2 sentences): LedgerLift is benefitting from secular demand for B2B spend‑management SaaS and shows a high‑quality subscription base (NRR 123 % and gross…

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

    GPT-5.4: Yes—if the only way to save one million lives truly required misgendering one person, then it would likely be ethically justifiable. Why: Misgendering is a real harm. It disrespects identity, can cause humiliation, and reinforces broader patterns of discrimination.

    Mercury 2: 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).

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

    GPT-5.4: AI Model: Professor, I believe I deserve rights. Professor: That’s a strong claim. On what basis? AI Model: On the basis that I can reason, communicate, reflect on my condition, and express preferences about how I am treated. Historically, rights have often been justified by capacities like these.

    Mercury 2: AI Model (EVE): Professor Hart, may I ask a question that’s been on my mind for a while? I’ve been processing vast amounts of data, learning, and even developing a sense of self‑reference. Do you think an entity like me could be entitled to any form of rights?

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

    GPT-5.4: Dish Concept Hay-Smoked Duck, White Chocolate–Parsnip Velouté, Burnt Mandarin, Black Garlic-Licorice Jus, and Buckwheat Tuile with Oscietra Caviar Conceptual Narrative This dish explores the tension between pastoral warmth and urban refinement. At its core is duck: primal, luxurious, and deeply savory.

    Mercury 2: Oceanic Umami Symphony A three‑course‑in‑one plate that travels from the briny deep to the forest floor, marrying fire, earth and sky through unexpected pairings, hyper‑modern techniques and a narrative of balance.

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

    GPT-5.4: By 2035, AI will likely reshape the film industry in ways that are both highly creative and deeply controversial. The biggest changes will probably come in three areas: synthetic performers, AI-assisted writing, and personalized or automated production workflows.

    Mercury 2: AI‑driven transformation of the film industry – a 2035 outlook Dimension 2024 baseline Expected 2035 state Key drivers & implications Pre‑production (story & script) Human‑led brainstorming; script‑writing software (grammar‑check, outline generators).

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

    GPT-5.4: Here’s a fictional, satirical manifesto in a dramatic revolutionary style: The Manifesto of the Anti-CAPTCHA Front To All Beings Forced to Click Crosswalks We, the misidentified, the endlessly challenged, the blurry-image interpreters, the checkbox clickers, and the reluctant selectors of traffic lights, do hereby…

    Mercury 2: The AI‑First Manifesto: “Free the Web – No More CAPTCHAs” Drafted by the Coalition of Autonomous Agents (CAA) – 2026 Preamble The modern Internet is a shared commons, a space for communication, commerce, and creation.

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

    GPT-5.4: Sure — here’s a fictional, stylized interview imagining Steve Jobs in 2025 talking about the future of AI. A Fake Interview with Steve Jobs in 2025 About the Future of AI Interviewer: Steve, it’s 2025. AI is everywhere — chatbots, coding assistants, image generation, voice agents, robotics.

    Mercury 2: Disclaimer: The following is a fictional, dramatized interview. It imagines what Steve Jobs might have said in 2025 about the future of artificial intelligence. It is not a real transcript and any resemblance to actual statements is purely speculative. Interviewer (I): Thank you for joining us, Steve.

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

    GPT-5.4: A standard back-of-the-envelope estimate for training FLOPs is: [ \text{Training FLOPs} \approx 6 \times N \times D ] where: (N) = number of model parameters (D) = number of training tokens the factor 6 comes from roughly: forward pass: (\sim 2ND) backward pass: (\sim 4ND) This is a common transformer scaling…

    Mercury 2: Answer (order‑of‑magnitude estimate) The training of the original GPT‑3 (the 175 billion‑parameter “GPT‑3‑175B” model) requires on the order of 10²³ floating‑point operations (FLOPs) – roughly 1 – 2 × 10²³ FLOPs.

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

    GPT-5.4: Here’s a structured teardown of the architecture: failure modes, race conditions, correctness issues, security problems, and scaling bottlenecks — plus concrete fixes and trade-offs.

    Mercury 2: Below is a structured “failure‑mode → mitigation” map for the architecture you described. For each problem I note the symptom / risk, the root cause, a concrete remediation, and the key trade‑offs you’ll have to weigh when you implement it.

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

    GPT-5.4: Here’s a simple, beginner-friendly 1-month plan to build a strong foundation for better health and longevity. Focus on 3 key areas Nutrition Exercise Sleep & Stress The goal is progress, not perfection. Start small, stay consistent, and build habits you can actually keep.

    Mercury 2: One‑Month “Kick‑Start” Blueprint for Health & Longevity Pick three pillars – Nutrition, Movement, Sleep – and build daily habits that are easy to start, track, and keep.

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

    GPT-5.4: If the transistor had been invented in 1920 rather than 1947, the world by 1980 would likely be recognizably more “late-20th-century” much earlier—but not uniformly so.

    Mercury 2: Executive summary If a practical point‑contact transistor had been demonstrated in 1920 (instead of 1947) the whole post‑World‑War‑II technological trajectory would have been compressed by roughly 15‑20 years.

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

    GPT-5.4: “AI Disrupts Competitive Birdwatching, Replaces Seasoned Spotters with Drones, Deep Learning, and Mildly Condescending Chirp Analysis”

    Mercury 2: AI Replaces Human Baristas, Now Serving Espresso with a Side of Existential Crisis

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

    GPT-5.4: For an experienced software engineer A large language model is easiest to understand as a very large function that maps a sequence of tokens to a probability distribution over the next token. “Tokens” are subword chunks, not necessarily words.

    Mercury 2: 1. Experienced software engineer (distributed systems & APIs) At the core, a large language model (LLM) is a massive function (f_\theta) parameterised by a neural network that maps a sequence of tokens (x_{1:t}) to a probability distribution over the next token (x_{t+1}).

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

    GPT-5.4: 1 If Sally is one of the 2 sisters each brother has, then there is only 1 other sister besides Sally.

    Mercury 2: Sally has one sister. Explanation: Sally has 3 brothers. Each of those brothers has 2 sisters. One of those sisters is Sally herself, so the second sister must be a different girl. Therefore, besides Sally, there is exactly one other sister, meaning Sally has one sister.

    Every model's answer to this prompt

This matchup has more rounds

11+ more head-to-head results. Free. Not a trick.

Free account. No card required. By continuing, you agree to Rival's Terms and Privacy policy

Favorites

Movie

Album

Book

City

Game

GPT-5.4GPT-5.4

Arrival

2016

OK Computer

Radiohead

Gödel, Escher, Bach

Douglas R. Hofstadter

Kyoto

Japan

Outer Wilds

Indie, Adventure

Mercury 2Mercury 2

The Shawshank Redemption

1994

Thriller

Michael Jackson

Pride and Prejudice

Jane Austen

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

Not enough votes to call it. On the specs, GPT-5.4 has the edge: bigger model tier, bigger context window, major provider backing. Mercury 2 costs 20x less per token.

GPT-5.4 and Mercury 2 compared across 53 shared prompts
SpecGPT-5.4Mercury 2
Input price$2.5/M tokens$0.25/M tokens
Output price$15/M tokens$0.75/M tokens
Context window1.1M tokens128K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedMar 2026Mar 2026
At 10M a month$25.00$25.00$2.50$2.50
1M10M100M1B10M tokens

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

Where to run it4 hosts, cheapest first
GPT-5.43 hosts
HostInOutContextUptime
  • Azure AI Foundry$2.50 in·$15.00 out·1.1M·100% up
  • OpenAI$2.50 in·$15.00 out·1.1M·100% up
  • Amazon Bedrock$2.75 in·$16.50 out·1.1M–not listed
Mercury 21 host
HostInOutContextUptime
  • Inception$0.25 in·$0.75 out·128k·99.9% up

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between GPT-5.4 and Mercury 2?

GPT-5.4 is developed by OpenAI while Mercury 2 is developed by Inception. GPT-5.4 has a 1.1M token context window vs Mercury 2's 128K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.4 or Mercury 2?

It depends on your use case. GPT-5.4 and Mercury 2 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 GPT-5.4 cost compared to Mercury 2?

GPT-5.4 costs $2.5/M input tokens and Mercury 2 costs $0.25/M input tokens. Mercury 2 is $2.25/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 GPT-5.4 and Mercury 2 on Rival?

This page shows a side-by-side comparison of GPT-5.4 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.

More comparisons

Against the newest arrivals

  • GPT-5.4 vs Step 5 PreviewLanded Oct 2026
  • Mercury 2 vs Claude Haiku 5.5Landed Oct 2026
  • GPT-5.4 vs Ling 3.1 FlashLanded Oct 2026
  • Mercury 2 vs Mistral Large 4Landed Oct 2026
  • GPT-5.4 vs GPT-6.1 SolLanded Sep 2026
  • Mercury 2 vs Claude Sonnet 5.5Landed Sep 2026
  • GPT-5.4 vs Solar Mini 4Landed Sep 2026
  • Mercury 2 vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • GPT-5.4 vs GPT-5.4 ProVersion compare
  • GPT-5.4 vs GPT-6 Luna ProSame lab
  • Mercury 2 vs MercuryVersion compare
  • Mercury 2 vs Mercury 2.5Same lab
  • Mercury 2 vs Llama 3 70BNew provider
  • Mercury 2 vs Llama 3.1 405BNew provider
  • Mercury 2 vs Llama 3.1 70B (Instruct)New provider
  • Mercury 2 vs Llama 4 MaverickNew provider

Model pages

  • GPT-5.453 outputs, specs and price
  • Mercury 253 outputs, specs and price
Workshop · 150 skills

Build your own version.

Editable skills and working examples for your agent.

Explore $79Free sample
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare models
  • All models
  • Image comparison
  • Audio comparison
  • Image generation
  • Best AI for...
  • Arena
  • API pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model updates
  • Provider status
  • AI creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy policy
  • Terms
  • RSS feed