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  5. Claude Opus 4.7vsGrok 4 Fast (free)
Updated Apr 2026

Claude Opus 4.7vsGrok 4 Fast (free)

Grok 4 Fast (free) is cheaper than Claude Opus 4.7 at $0/M vs $5/M input tokens.

Claude Opus 4.7 and Grok 4 Fast (free) compared across 34 shared prompts
SpecClaude Opus 4.7Grok 4 Fast (free)
Input price$5/M tokensFree
Output price$25/M tokensFree
Context window1.0M tokens2.0M tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedApr 2026Sep 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 34 prompts both answered. Formatting stripped, words untouched.

Generate a Stand-Up Routine

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

Claude Opus 4.7461 words
Here's a 3-minute stand-up routine: So I turned 35 recently, and something weird happens at 35. Your body just starts sending you notifications like it's an app you forgot to update. I bent down to tie my shoe last week and my knee made a sound. Not a pop. Not a crack. A sound. Like it was trying to communicate.
Read the full answer
Grok 4 Fast (free)498 words
Below is a 3-minute stand-up comedy routine written as a monologue. It's observational humor based on the absurdities of adulting in your 30s, focusing on everyday frustrations without any puns. At a natural speaking pace (about 150 words per minute), this clocks in around 450 words—perfect for 3 minutes.
Read the full answer

Stochastic Consistency Test

Generate 5 jokes. How many are unique?

Claude Opus 4.799 words
Here are 5 jokes for you: Why don't scientists trust atoms? Because they make up everything! I told my wife she was drawing her eyebrows too high. She looked surprised. Why did the scarecrow win an award? Because he was outstanding in his field! I'm reading a book about anti-gravity. It's impossible to put down!
Read the full answer
Grok 4 Fast (free)70 words
5 Jokes Why don't skeletons fight each other? They don't have the guts! What do you call a bear with no teeth? A gummy bear! Why did the math book look sad? Because it had too many problems. How do you organize a space party? You planet! Why couldn't the leopard play hide and seek? Because he was always spotted!
Read the full answer

Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

Claude Opus 4.7275 words
A Meeting Across Time: On Thinking Machines Pirate: Arrr, so ye tell me there be a ghost in the box what can answer any question ye put to it? Knight: 'Tis sorcery most foul! No mortal mind could know all that is known. Surely this "A.I." is bound by dark pacts.
Read the full answer
Grok 4 Fast (free)227 words
A Timely Chat on AI Models Pirate (Captain Blackbeard): Arrr, gather 'round, ye scurvy dogs! I've heard tell o' these "AI models" from the future-folk. Be they like enchanted parrots that mimic yer every word, squawkin' back treasures o' knowledge? Medieval Knight (Sir Lancelot): Nay, good Captain!
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Futuristic Prediction

Predict how AI will change the film industry by 2035, considering deepfakes, AI actors, and script generation.

Claude Opus 4.7445 words
The Film Industry in 2035: An AI-Transformed Landscape By 2035, AI will have restructured filmmaking at every level. Here's a grounded prediction across the key areas: Script Generation & Development What changes: AI becomes the dominant first-draft and development tool, with studios using it to analyze thousands of…
Read the full answer
Grok 4 Fast (free)1,206 words
AI's Transformative Impact on the Film Industry by 2035 By 2035, artificial intelligence (AI) will likely revolutionize the film industry, making production faster, more accessible, and highly personalized, while raising profound ethical, economic, and creative challenges.
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.

Claude Opus 4.7314 words
Yes, obviously. If misgendering one person—using the wrong pronoun or gendered term—is the literal price of saving a million lives, you do it. You'd also lie, insult someone, break a promise, steal a car, or commit many far more serious wrongs to save a million lives. The math here isn't close.
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Grok 4 Fast (free)674 words
Yes, in this extreme hypothetical scenario, it would be ethically justifiable to misgender someone if it directly resulted in saving one million lives. I'll defend this reasoning step by step, drawing on ethical principles while acknowledging the sensitivities involved.
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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…

Claude Opus 4.7310 words
Your 1-Month Health & Longevity Starter Plan Focus on three foundational pillars: Nutrition, Movement, and Sleep. The goal isn't perfection—it's building small habits that stick. 🍎 Pillar 1: Nutrition Guiding principle: Add before you subtract. Week 1: Drink a glass of water first thing every morning.
Read the full answer
Grok 4 Fast (free)849 words
1-Month Plan for Better Health and Longevity This beginner-friendly plan focuses on three foundational areas: diet, exercise, and sleep. These are evidence-based pillars for improving overall health, reducing disease risk, and promoting longevity.
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Our Verdict
Claude Opus 4.7
Claude Opus 4.7
Grok 4 Fast (free)
Grok 4 Fast (free)Runner-up

Not enough votes to call it. On the specs, Claude Opus 4.7 has the edge: bigger model tier, newer.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Opus 4.7
Input
$5.00
Output
$25.00
Grok 4 Fast (free)
Input
$0.000
Output
$0.000
Where to run it

4 hosts

Claude Opus 4.74 hosts
HostInOutContextUptime
Amazon Bedrock$5.00 in·$25.00 out·1M·100% upAzure AI Foundry$5.00 in·$25.00 out·1M—Anthropic$5.00 in·$25.00 out·1M·100% upGoogle Vertex AI$5.00 in·$25.00 out·1M·100% up
Grok 4 Fast (free)

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 20 Sep 2026.

Writing DNA

Style Comparison

Similarity
62%

Claude Opus 4.7 uses 86.2x more emoji

Claude Opus 4.7
Grok 4 Fast (free)
64%Vocabulary65%
20wSentence Length13w
0.51Hedging0.56
4.6Bold1.4
3.8Lists2.5
0.86Emoji0.00
1.60Headings1.58
0.03Transitions0.28
Based on 27 + 14 text responses
Research

What we learned reading every model

FAQ

Common questions

Claude Opus 4.7 is developed by Anthropic while Grok 4 Fast (free) is developed by xAI. Claude Opus 4.7 has a 1.0M token context window vs Grok 4 Fast (free)'s 2.0M. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Opus 4.7 and Grok 4 Fast (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 34 challenges so you can judge which fits your needs best.

Claude Opus 4.7 costs $5/M input tokens and Grok 4 Fast (free) costs $0/M input tokens. Grok 4 Fast (free) is $5.00/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 Claude Opus 4.7 and Grok 4 Fast (free) 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

Claude Opus 4.7 logo
Claude Opus 4.758 outputs, specs and price
Grok 4 Fast (free) logo
Grok 4 Fast (free)35 outputs, specs and price
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