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  5. Mercury 2.5vsOpenAI o3
Updated Sep 2026

Mercury 2.5vsOpenAI o3

Mercury 2.5 is cheaper than OpenAI o3 at $0.04/M vs $10/M input tokens.

Mercury 2.5 and OpenAI o3 compared across 20 shared prompts
SpecMercury 2.5OpenAI o3
Input price$0.04/M tokens$10/M tokens
Output price$0.15/M tokens$40/M tokens
Context window260K tokens—
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedSep 2026Apr 2025
Side by side

Same prompt, both answers

Opening lines from 4 of the 20 prompts both answered. Formatting stripped, words untouched.

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…

Mercury 2.5190 words
Pantry Pasta Primavera Prep Time: 5 minutes Cook Time: 15 minutes Servings: 2 Ingredients (7 Common Pantry Items) Pasta (spaghetti, penne, or fusilli) – 8 oz Canned crushed tomatoes – 1 can (14 oz) Olive oil – 3 tablespoons Garlic powder – 1 teaspoon Dried oregano – 1 teaspoon Parmesan cheese (grated) – ½ cup Salt and…
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OpenAI o3279 words
Golden Peanut Butter Oat Bars A chewy-crisp, sweet-salted snack bar you can whip up with nothing but pantry staples. Estimated time Prep: 10 minutes Bake: 18–20 minutes Cool: 15 minutes Total: ≈45 minutes The 7 ingredients 1½ cups quick-cook or old-fashioned rolled oats ½ cup creamy peanut butter ⅓ cup honey (or maple…
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…

Mercury 2.5325 words
Here is a simple, actionable 1-month plan to kickstart your journey toward better health and longevity. This guide focuses on three foundational pillars: Nutrition, Movement, and Sleep. Week 1: Awareness & Small Wins Goal: Build habits without overwhelming yourself.
Read the full answer
OpenAI o3336 words
1-Month Starter Plan Pick one small action from each area every week. Add the next step when the first feels easy. Food Week Do this 1 Add one fruit or veg to every meal. Drink one extra glass of water. 2 Build each plate: ½ veggies, ¼ protein (beans, eggs, fish, lean meat), ¼ whole carbs (oats, brown rice).
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Michelin Star Recipe Design

Design an innovative recipe for a multi-component dish worthy of a Michelin 3-star restaurant. The recipe should feature an unusual…

Mercury 2.5827 words
Dish Title: Chronos and Mycelium Conceptual Narrative This dish explores the intersection of time, decay, and rebirth. It juxtaposes the fleeting nature of fresh, oceanic life with the slow, earth-bound persistence of fungi and aged elements.
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OpenAI o3669 words
Dish name Atlantic turbot, black garlic & wild strawberry, koji sabayon, fennel pollen Concept Early summer at the shore. The fish stands for the sea. Wild strawberries mark the first fruit of the woods behind the dunes. Black garlic shows time and patience. Koji ties land and sea with deep umami.
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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…

Mercury 2.5610 words
3-Month Biohacking Longevity & Performance Plan Disclaimer: I am an AI, not a physician or certified health professional. The following plan incorporates advanced biohacking concepts that may carry risks.
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OpenAI o3905 words
EXTREME LONGEVITY & PERFORMANCE BLUEPRINT Duration: 12 weeks (plus 1-week "Prep Week") Target user: healthy, experienced biohacker (25-55 y) with physician clearance. Legal/medical disclaimer: Educational only.
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Our Verdict
OpenAI o3
OpenAI o3
Mercury 2.5
Mercury 2.5Runner-up

Not enough votes to call it. On the specs, OpenAI o3 has the edge: bigger model tier, major provider backing.

Mercury 2.5 costs 267x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Mercury 2.5
Input
$0.04
250× cheaper
Output
$0.15
267× cheaper
OpenAI o3
Input
$10.00
Output
$40.00

Mercury 2.5 is cheaper on both: 250× input, 267× output.

Where to run it

2 hosts

Mercury 2.51 host
HostInOutContextUptime
Inception$0.04 in·$0.15 out·260k·100% up
OpenAI o31 host
HostInOutContextUptime
OpenAI$2.00 in·$8.00 out·200k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 22 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Mercury 2.5 is developed by Inception while OpenAI o3 is developed by OpenAI. You can compare their actual outputs across 20 challenges on Rival to see how they differ in practice.

It depends on your use case. Mercury 2.5 and OpenAI o3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 20 challenges so you can judge which fits your needs best.

Mercury 2.5 costs $0.04/M input tokens and OpenAI o3 costs $10/M input tokens. Mercury 2.5 is $9.96/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 Mercury 2.5 and OpenAI o3 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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