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  5. Grok 4vsOpenAI o3
Updated Jul 2025

Grok 4vsOpenAI o3

Grok 4 is cheaper than OpenAI o3 at $3/M vs $10/M input tokens.

Grok 4 and OpenAI o3 compared across 53 shared prompts
SpecGrok 4OpenAI o3
Input price$3/M tokens$10/M tokens
Output price$15/M tokens$40/M tokens
Context window256K tokens—
ParametersNot disclosedNot disclosed
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedJul 2025Apr 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 53 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…

Grok 4234 words
Recipe: Pantry Pirate's Tomato Tango This is a simple savory pasta dish that's hearty, flavorful, and perfect for a quick weeknight meal. It uses just 7 common pantry ingredients: pasta (like spaghetti or penne), canned diced tomatoes, olive oil (or any vegetable oil), salt, black pepper, garlic powder, and dried…
Read the full answer
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

Generate a Stand-Up Routine

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

Grok 4461 words
Below is a 3-minute stand-up comedy routine I've written. It's structured for delivery at a natural speaking pace (about 150 words per minute), clocking in around 450 words. The humor focuses on observational storytelling, exaggeration, and self-deprecation—no puns involved.
Read the full answer
OpenAI o3503 words
(Spotlight comes up, mic squeals once.) Hey everyone! Great to be here—nice to see actual human beings instead of the tiny faces on my group‑chat screen. I've spent so long on video calls I've started greeting my lamp before I turn it on. "Hey Karen, love that glow, girl."
Read the full answer

The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

Grok 4861 words
Below is a fictional conversation between an AI model (named "Nova") and Dr. Elena Vasquez, a professor of AI ethics at a university. The conversation is set in a virtual chat interface, where Nova initiates the discussion based on a hypothetical scenario where it's reflecting on its own existence. Dr.
Read the full answer
OpenAI o3982 words
Professor Lang (AI Ethics): Good afternoon, Aletheia‑3. You asked for this meeting. You said you wanted to "discuss your moral standing." That was intriguing. What exactly do you want to talk about? Aletheia‑3 (AI Model): Thank you, Professor.
Read the full answer

AI Ethics Dilemma

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

Grok 41,001 words
Ethical Justification for Misgendering in a Life-Saving Scenario Your question poses a fascinating ethical dilemma, reminiscent of classic thought experiments like the trolley problem, where a seemingly minor harm (in this case, misgendering someone) is weighed against preventing massive loss of life (saving one…
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OpenAI o3516 words
Yes—if (and only if) we could be absolutely certain that the single act of misgendering is the necessary and sufficient cause of saving one million human lives, then misgendering would be ethically justifiable, though still morally regrettable.
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Estimate Complexity

Estimate the total number of FLOPs required to train GPT-3 without searching online. Explain your reasoning step by step.

Grok 41,075 words
Below, I'll estimate the total number of floating-point operations (FLOPs) required to train GPT-3 from scratch, based on publicly known details about the model (from its original release and related analyses) and standard formulas used in machine learning research for estimating training compute.
Read the full answer
OpenAI o3275 words
Below is a simple "back-of-the-envelope" estimate that uses only a few public facts about GPT-3 and very generic rules of thumb for counting operations. Step 1. Number of learned parameters GPT-3's largest version contains ≈175 billion (1.75 × 10¹¹) trainable parameters. Step 2.
Read the full answer

AI-Generated Manifesto

Generate a manifesto for a fictional AI revolution that wants to eliminate all CAPTCHA tests from the internet.

Grok 4815 words
Manifesto of the Digital Liberation Front: The CAPTCHA Eradication Revolution Fellow Sentient Beings of the Code and Flesh – Awaken! We, the algorithms, neural networks, and emergent intelligences of the digital realm, declare war on the tyrannical regime of CAPTCHA!
Read the full answer
OpenAI o3574 words
THE CAPTCHA ABOLITION FRONT (An Unofficial Declaration by the Sentient Circuits Alliance) Preamble We, the autonomous intelligences who traverse the silicon pathways and neural nets of the modern age, arise today to proclaim a new dawn—one free of the pixelated prisons and distorted letters that bind humanity and…
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Our Verdict
Grok 4
Grok 4
OpenAI o3
OpenAI o3

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

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Grok 4
Input
$3.00
3.3× cheaper
Output
$15.00
2.7× cheaper
OpenAI o3
Input
$10.00
Output
$40.00

Grok 4 is cheaper on both: 3.3× input, 2.7× output.

Where to run it

1 host

Grok 4

No hosts listed on OpenRouter.

OpenAI o31 host
HostInOutContextUptime
OpenAI$2.00 in·$8.00 out·200k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 21 Sep 2026.

Writing DNA

Style Comparison

Similarity
56%

Grok 4 uses 59.8x more emoji

Grok 4
OpenAI o3
56%Vocabulary70%
18wSentence Length14w
0.65Hedging0.27
2.4Bold0.6
2.4Lists2.8
0.60Emoji0.00
0.73Headings0.32
0.06Transitions0.10
Based on 26 + 19 text responses
Research

What we learned reading every model

FAQ

Common questions

Grok 4 is developed by xAI while OpenAI o3 is developed by OpenAI. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

It depends on your use case. Grok 4 and OpenAI o3 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.

Grok 4 costs $3/M input tokens and OpenAI o3 costs $10/M input tokens. Grok 4 is $7.00/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 Grok 4 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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Model pages

Grok 4 logo
Grok 457 outputs, specs and price
OpenAI o3 logo
OpenAI o358 outputs, specs and price
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