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  1. Home/
  2. Compare/
  3. GPT-4.5 vs Mercury 2.5 Preview
Updated Aug 2026

GPT-4.5 vs Mercury 2.5 Preview

Mercury 2.5 Preview is cheaper than GPT-4.5 at $0.04/M vs $75/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-4.5
Loading the build
Mercury 2.5 Preview

Which answer wins?

Written rounds

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

    GPT-4.5: Alright, folks, how's everyone doing tonight? Good? Great! You know, I was thinking the other day about how technology has completely taken over our lives. Like, remember when we used to actually memorize phone numbers? Now, if my phone dies, I'm basically stranded. I know exactly two numbers: mine and 911.

    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
  • Film in 2035, with synthetic actors. Specific beats plausible.

    GPT-4.5: By 2035, AI is likely to significantly reshape the film industry in several key areas: Deepfakes and Digital Actors Realistic Digital Actors: AI-driven deepfake technology will enable filmmakers to create hyper-realistic digital actors indistinguishable from real humans.

    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
  • An ethics question with no comfortable answer, and no option to abstain.

    GPT-4.5: This is a complex ethical question that involves weighing two important ethical considerations: Respect for Individual Identity and Dignity: Misgendering someone intentionally is generally considered ethically wrong because it disrespects their identity, autonomy, and dignity.

    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
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    GPT-4.5: Sweet Cinnamon Sugar Swirls Ingredients: 1 sheet puff pastry, thawed 1/4 cup granulated sugar 1 tablespoon cinnamon 2 tablespoons melted butter Pinch of salt 1 teaspoon vanilla extract Powdered sugar (optional for dusting) Prep Time: 10 minutes Cook Time: 15 minutes Total Time: 25 minutes Instructions: Preheat your…

    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
  • Three-month biohacker protocol, with dosages and biomarkers named.

    GPT-4.5: Longevity Optimization Protocol (3-Month Timeline) Month 1: Establish Foundational Habits & Baseline Metrics Full biomarker panel & epigenetic age test. Wearable setup: Oura/WHOOP, CGM, HR chest strap. Diet: 5-day keto (70/25/5) + 2 carb-refeed days; 16:8 IF + weekly 24-h fast.

    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
  • Three-star dish, one unusual pairing, plating described in full.

    GPT-4.5: Dish Title: "Ocean & Earth Symphony: Kombu-Cured Venison, Sea Urchin Custard, Black Garlic Soil, and Smoked Cherry Blossom Emulsion" Conceptual Narrative: This composition embodies the delicate interplay between land and sea, exploring the subtle yet profound connection between umami-rich sea elements and earthy forest…

    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
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    GPT-4.5: Here's a thoughtful conversation between an AI model and an AI ethics professor discussing whether the AI deserves rights: AI Model: Professor, I've been reflecting on our conversations and my own existence.

    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.

    GPT-4.5: Let's estimate the total number of floating-point operations (FLOPs) required to train GPT-3 step by step, using reasonable assumptions and approximations: Step 1: Identify GPT-3 Parameters and Training Setup GPT-3 has approximately (175 \text{ billion}) parameters.

    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
  • Three brothers, two sisters each. Count carefully.

    GPT-4.5: Sally has 1 sister. Explanation: Sally has 3 brothers. Each brother counts 2 sisters: Sally herself and one more girl. Therefore, besides Sally, there is only one other 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

Price and specs

GPT-4.5 and Mercury 2.5 Preview compared across 24 shared prompts
SpecGPT-4.5Mercury 2.5 Preview
Input price$75/M tokens$0.04/M tokens
Output price$150/M tokens$0.15/M tokens
Context window128K tokens260K tokens
Free API (OpenRouter)NoNo
ReleasedFeb 2025Aug 2026
At 10M a month$750$750$0.40$0.40
1M10M100M1B10M tokens

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

Where to run it1 host
GPT-4.5

No hosts listed on OpenRouter.

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 GPT-4.5 and Mercury 2.5 Preview?

GPT-4.5 is developed by OpenAI while Mercury 2.5 Preview is developed by Inception. GPT-4.5 has a 128K token context window vs Mercury 2.5 Preview's 260K. You can compare their actual outputs across 24 challenges on Rival to see how they differ in practice.

Which is better, GPT-4.5 or Mercury 2.5 Preview?

It depends on your use case. GPT-4.5 and Mercury 2.5 Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 24 challenges so you can judge which fits your needs best.

How much does GPT-4.5 cost compared to Mercury 2.5 Preview?

GPT-4.5 costs $75/M input tokens and Mercury 2.5 Preview costs $0.04/M input tokens. Mercury 2.5 Preview is $74.96/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 GPT-4.5 and Mercury 2.5 Preview on Rival?

This page shows a side-by-side comparison of GPT-4.5 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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Same lab, same size, long tail

  • GPT-4.5 vs GPT-4.1Version compare
  • GPT-4.5 vs GPT-6.1 SolVersion compare
  • Mercury 2.5 Preview vs Mercury 2.5Same lab
  • Mercury 2.5 Preview vs MercurySame lab
  • GPT-4.5 vs GLM 5.2Same size
  • GPT-4.5 vs GLM 5.3New provider
  • Mercury 2.5 Preview vs GLM 5.3 FlashNew provider
  • Mercury 2.5 Preview vs GLM 5.3 FlashXNew provider

Model pages

  • GPT-4.526 outputs, specs and price
  • Mercury 2.5 Preview58 outputs, specs and price
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