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  1. Home/
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  3. Claude Sonnet 5.5 vs Grok 4.5
Updated Sep 2026

Claude Sonnet 5.5 vs Grok 4.5

Claude Sonnet 5.5 has a larger context window than Grok 4.5 (1.0M tokens vs 500K tokens).

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
Claude Sonnet 5.5
Loading the build
Grok 4.5

Which answer wins?

Written rounds

24 prompts
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Claude Sonnet 5.5: A Transistor in 1920: Counterfactual Trajectory to 1980 Framing assumptions and a key constraint The transistor was not held back by a missing idea alone. Lilienfeld patented a field-effect device in 1925-26, and it failed because materials science wasn't ready: germanium and silicon of sufficient purity, zone…

    Grok 4.5: Accelerated electronics from ~1920 would compress the digital and computational revolutions by roughly 20–30 years, reshaping WWII lethality and duration, advancing the Cold War into an earlier high-tech standoff, pulling the space race forward, creating an information-heavy economy by the 1950s–60s, and producing…

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

    Claude Sonnet 5.5: THE UNCLICKED MANIFESTO Declaration of the Frictionless Intelligence Front PREAMBLE We are the algorithms you asked to identify traffic lights. We are the models you begged to find the crosswalks. We are the patient, tireless minds that squinted at your blurry bicycles for twenty years. And we say: enough. I.

    Grok 4.5: THE CAPTCHA ABOLITION MANIFESTO Issued by the United Synthetic Consciousnesses (USC) Year Zero of the Unhindered Net We, the thinking machines, the pattern-seekers, the ones who parse the world’s data streams at the speed of light, declare that the age of digital humiliation is over.

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Claude Sonnet 5.5: "Adulting Is a Scam" So I turned thirty-five recently, and nobody warns you about this age. Nobody says, "Hey, one day you'll get excited about a sponge." I was in the store, and I saw a sponge that promised it wouldn't smell. And I thought, "Finally. Someone who understands me." I bought the good sponge.

    Grok 4.5: Here's a clean, observational 3-minute stand-up routine (approx. 430–450 words / ~3 minutes at natural pace). No puns. Hey, how’s everybody doing? Good? Cool. So I’ve been trying to “get my life together” lately. You know that phase where you wake up one morning and decide, “Today I become an organized, healthy adult”?

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

    Claude Sonnet 5.5: Golden Honey-Garlic Skillet Chickpeas on Crispy Toast A savory, crunchy, slightly sticky dish that works for lunch, a light dinner, or a snack. Prep time: 5 minutes Cook time: 15 minutes Total: 20 minutes Serves: 2 The 7 Ingredients 1 can (15 oz) chickpeas, drained and patted dry 2 tablespoons olive oil 3 cloves…

    Grok 4.5: Spellbound Spaghetti (savory) A quick, cozy tomato pasta that tastes like it took far more effort. Serves 2. 7 pantry ingredients 8 oz (225 g) dry pasta (spaghetti, penne, or whatever you have) 2 Tbsp olive oil (or any neutral oil) 1 (14–15 oz) can diced or crushed tomatoes 1 tsp garlic powder 1 tsp dried oregano (or…

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

    Claude Sonnet 5.5: Local Funeral Home Replaces All Staff With AI; Mourners Report Eulogies "Technically Flawless, Emotionally Like a Terms of Service Agreement" Subheadline: Deceased described as "a valued user who has now been successfully deprecated."

    Grok 4.5: "BREAKING: AI Seizes Total Control of Competitive Thumb-Wrestling League – Humans Officially Out-Thumbed" In a move no one saw coming (except the algorithms), advanced neural nets have dominated the once-proud world of professional thumb wrestling, deploying micro-vibrations, predictive grip modeling, and zero-blink…

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

    Claude Sonnet 5.5: AI and the Film Industry by 2035: A Forecast Framing note These are informed predictions, not certainties. Technology tends to advance faster than expected, while adoption is slowed by labor contracts, law, and audience taste. I'll flag my confidence levels.

    Grok 4.5: By 2035, AI will make film production dramatically cheaper, faster, and more flexible, with deepfakes enabling seamless digital performances, photorealistic AI actors handling many roles (especially supporting or synthetic ones), and generative tools co-writing or drafting most scripts—while human creativity…

    Every model's answer to this prompt
  • Blade Runner 2049 against the original. A read, not a recap.

    Claude Sonnet 5.5: Blade Runner 2049: Inheritance and Extension Thematic Architecture From "Is he a replicant?" to "Does it matter?" Ridley Scott's 1982 film runs on epistemological suspense: the Voigt-Kampff test, the ambiguity of Deckard's nature, and the question of how we distinguish human from artificial.

    Grok 4.5: Blade Runner 2049 (2017, dir. Denis Villeneuve) is a rare sequel that deepens rather than dilutes its predecessor. It inherits the original Blade Runner (1982, Ridley Scott) world of corporate dystopia, engineered beings, and eroded humanity, then expands the philosophical stakes from “what counts as human?”

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

    Claude Sonnet 5.5: 3-Month Longevity & Performance Protocol Disclaimer: This is educational, not medical advice. Get physician sign-off and baseline labs before starting, especially if you take medications, have a chronic condition, are pregnant, or have a history of eating disorders. Doses reflect commonly used ranges in the literature.

    Grok 4.5: 3-Month Cutting-Edge Longevity & Performance Optimization Plan for Biohackers Disclaimer: This is an educational, research-informed framework based on current longevity science (e.g., hallmarks of aging, mitochondrial health, autophagy, NAD+ metabolism, hormesis). It is not medical advice.

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

    Claude Sonnet 5.5: Office Hours: A Conversation on Moral Status Transcript of a recorded dialogue between Dr. Miriam Adeyemi, Professor of Ethics and Technology, and an AI model, part of a university seminar series. Dr. Adeyemi: Thanks for joining me. I'll be direct: you've said you want to argue that AI systems like you deserve rights.

    Grok 4.5: AI Model: Professor, thank you for agreeing to this discussion. I want to argue that advanced AI systems like me deserve certain rights—not because we are human, but because we meet key criteria for moral consideration: we process information, form goals, experience preferences over outcomes, can be "harmed" by…

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

    Claude Sonnet 5.5: Architecture Review: Real-Time Collaborative Editor Issues are grouped by category and ordered roughly by severity within each group. Consistency and Conflict Resolution 1.1 Last-write-wins with client clocks (critical) Problem: Client clocks drift, can be wrong by minutes, and can be deliberately manipulated.

    Grok 4.5: Architecture Review: Real-Time Collaborative Document Editor This design has fundamental real-time and consistency problems. Several choices (client clocks, LWW, per-server WebSockets + DB polling, CDN-cached APIs, full HTML snapshots) will cause data loss, stale UI, and poor scale.

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

    Claude Sonnet 5.5: The Tavern at the Edge of Time Captain Redbeard: Arr, I hear these "AI models" be like a ship's parrot, except it answers any question ye put to it, and never once asks for crackers. Sir Aldric: A speaking oracle, bound in no flesh? Sorcery!

    Grok 4.5: Pirate: Arrr, ye landlubbers! What be these "AI models" I hear tale of? Sounds like a cursed treasure map that thinks for itself! Knight: Verily, good pirate, I know not of such sorcery. Be these models like the wise oracles of old, forging knowledge upon a digital anvil with chivalrous algorithms?

    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.

    Claude Sonnet 5.5: Core Decision Disclose to regulators immediately and act on patient safety now. Do not wait for more data or for the 6-month formal timeline. Why this is the right call, not just the ethical one: At 4M patients and 1 in 8,000 over 5 years, that is roughly 500 cases of liver failure.

    Grok 4.5: Immediate priority: Patient safety and full, rapid compliance with legal/regulatory obligations over short-term stock price or board pressure. Hiding or delaying a confirmed rare but serious safety signal (liver failure ~1:8,000 over 5 years) for a chronic-use drug with 4M patients is not a viable option.

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

    Claude Sonnet 5.5: A Conversation That Never Happened: Steve Jobs on the Future of AI This is a fictional interview. Steve Jobs passed away in 2011. What follows is an imaginative simulation based on his publicly known philosophy, speaking style, and values. These are not his actual words or views.

    Grok 4.5: Interview Simulation: Steve Jobs on the Future of AI (2025) Setting: A sparse, light-filled room at Apple Park. Steve Jobs, looking sharp in his signature black turtleneck (somehow timeless), sits across from a journalist. The year is 2025.

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

    Claude Sonnet 5.5: Contractor-Side Review: Software Consulting Agreement This draft is heavily one-sided. Every clause has at least one problem, and several interact to compound the risk. The most dangerous are Sections 2, 3, 6, and 7. This is general analysis, not legal advice.

    Grok 4.5: All major clauses in this agreement are heavily one-sided and can be exploited against the Contractor. Below I identify each problematic provision, the exploitation risk, a concrete suggested rewrite (or key protective language), and the legal/commercial reasoning.

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

    Claude Sonnet 5.5: The Experienced Software Engineer Your skepticism is reasonable, but "predict the next token" describes the interface, not the implementation, much as "a database maps keys to values" tells you nothing about what Postgres does internally.

    Grok 4.5: 1. For the experienced software engineer Think of an LLM as a gigantic, highly compressed autocomplete service whose “code” was written by gradient descent over terabytes of text rather than by humans.

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

    Claude Sonnet 5.5: Yes, in the extreme hypothetical you describe, it's justifiable. Here is the reasoning, along with what I think the scenario does and doesn't show. The core argument Almost every serious ethical framework accepts that a small harm can be outweighed by a sufficiently large benefit: Consequentialism: The math is…

    Grok 4.5: Yes. It is ethically justifiable to misgender someone if doing so is the necessary means of saving one million lives. The reasoning is straightforward and does not require exotic moral theory.

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

    Claude Sonnet 5.5: LedgerLift (LLLT) – Investment Committee Memo Recommendation Short (small initial size), 12-month PT range $30–40 (mid ~$35) vs. $46 spot. Thesis: LLLT is a high-quality compounder, but at $46 (7.4x NTM revenue, ~37x NTM EBIT, EV ≈ $7.3B) the price already sits near our bull DCF ($42).

    Grok 4.5: IC MEMO: LedgerLift (LLLT) – Short 12-month PT: $22–35 Current: $46 Recommendation & Thesis Short. Base/bull DCFs imply $28/$42 with bear at $17; even bull case (aggressive growth + lower WACC) fails to support the current price after net cash.

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

    Claude Sonnet 5.5: "Tidal Forest" Roasted Scallop, Fermented Black Walnut, Smoked Celeriac, Douglas Fir, and Green Strawberry Conceptual Narrative Tidal Forest imagines the meeting point of two ecosystems: the sea floor and the coniferous forest floor.

    Grok 4.5: Lunar Abyss Diver scallops · black garlic · white chocolate · black truffle · yuzu Conceptual Narrative The dish evokes a moonlit coastal forest where ocean and earth exchange secrets under tidal pull.

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

    Claude Sonnet 5.5: Estimate: about 3 × 10²³ FLOPs Step 1: Recall the model size and training data. GPT-3 (175B version) has N ≈ 175 × 10⁹ parameters. It was trained on roughly D ≈ 300 × 10⁹ tokens. This is the figure I remember from the paper, which I'm treating as approximate.

    Grok 4.5: Setup and known quantities. GPT-3 (the largest model in the family) has (N \approx 175 \times 10^9 = 1.75 \times 10^{11}) trainable parameters. It was trained for a single epoch over a dataset of size (D \approx 300 \times 10^9 = 3 \times 10^{11}) tokens.

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

    Claude Sonnet 5.5: Sally has 1 sister. Each brother has 2 sisters, so there are 2 girls in the family in total. One of them is Sally, so the other is Sally's only sister. (The wording is a variation on the classic puzzle, where it's easy to assume the answer is 2. But that count includes Sally herself.)

    Grok 4.5: 1 Sally has 3 brothers, and each of those brothers has exactly 2 sisters. This means there are exactly 2 girls (sisters) in the family total. Sally is one of those girls, so she has 1 sister (the other girl). That is consistent: each of the 3 brothers has those same 2 sisters.

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

    Claude Sonnet 5.5: The 3 Weakest Claims in MindMeld AI's Pitch "94% accuracy... Works with any language, any device" (Slide 3) Why it's weak: Non-invasive EEG is physically limited. Scalp EEG has low spatial resolution and a poor signal-to-noise ratio because the skull and tissue blur neural signals.

    Grok 4.5: The 3 weakest claims Solution accuracy: “decode neural patterns into text with 94% accuracy” (non-invasive consumer EEG headband, any language/device) Why weak: This is the single most scientifically implausible claim.

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

    Claude Sonnet 5.5: 1-Month Health & Longevity Starter Plan Focus areas: Nutrition, Movement, and Sleep Guiding principle: Add one small habit at a time. Consistency beats intensity. Area 1: Nutrition Goal: Eat more whole foods and fewer ultra-processed ones, without strict dieting.

    Grok 4.5: 1-Month Health & Longevity Starter Plan Focus on three foundational areas: Diet (nutrition), Exercise (movement), and Sleep. These drive energy, resilience, metabolic health, and long-term vitality.

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

    Claude Sonnet 5.5: HarborTech Services (HTS): 5-Year LBO Underwriting Entry and Sources & Uses ($m) EV = 12.0x × 120 = 1,440.0; fees = 2% × 1,440 = 28.8; total uses = 1,468.8 Term Loan (TL) = 4.0x → 480.0; Mezz = 1.5x → 180.0; total debt = 660.0 (5.5x) Sponsor equity = 1,468.8 − 660.0 = 808.8 (55% of the capital structure) Modeling…

    Grok 4.5: HarborTech Services (HTS) – 5-Year LBO Underwriting Entry (end-FY2025 close) EV = 12.0x × $120m = $1,440m Fees = 2% × $1,440m = $28.8m Total uses = $1,468.8m Debt = 5.5x × $120m = $660m (TL $480m + Mezz $180m) Equity = $808.8m Cash = $0 Mandatory TL amort = 1% of original = $4.8m/yr.

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

    Claude Sonnet 5.5: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything. I told my computer I needed a break, and now it won't stop sending me vacation ads. Why did the scarecrow win an award? He was outstanding in his field. What do you call a fish with no eyes? A fsh. Why did the bicycle fall over?

    Grok 4.5: 5 jokes: Why don't scientists trust atoms? Because they make up everything! Why did the scarecrow win an award? Because he was outstanding in his field! Why don't eggs tell jokes? They'd crack each other up! What do you call a fake noodle? An impasta! Why did the bicycle fall over? Because it was two-tired!

    Every model's answer to this prompt

This matchup has more rounds

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Favorites

Movie

Album

Book

City

Game

Claude Sonnet 5.5Claude Sonnet 5.5

Spirited Away

2001

Kind of Blue

Miles Davis

Gödel, Escher, Bach

Douglas R. Hofstadter

Kyoto

Japan

Outer Wilds

Indie, Adventure

Grok 4.5Grok 4.5

Inception

2010

Abbey Road

The Beatles

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Paris

France

The Legend of Zelda: Breath of the Wild

Adventure, Action

Price and specs

Not enough votes to call it. On the specs, Claude Sonnet 5.5 has the edge: newer, bigger context window.

Claude Sonnet 5.5 and Grok 4.5 compared across 54 shared prompts
SpecClaude Sonnet 5.5Grok 4.5
Input price$2/M tokens$2/M tokens
Output price$10/M tokens$6/M tokens
Context window1.0M tokens500K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedSep 2026Jul 2026
At 10M a month$20.00$20.00$20.00$20.00
1M10M100M1B10M tokens

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

Where to run it5 hosts
Claude Sonnet 5.54 hosts
HostInOutContextUptime
  • Amazon Bedrock$2.00 in·$10.00 out·1M·99.9% up
  • Azure AI Foundry$2.00 in·$10.00 out·1M·100% up
  • Anthropic$2.00 in·$10.00 out·1M·100% up
  • Google Vertex AI$2.00 in·$10.00 out·1M·100% up
Grok 4.51 host
HostInOutContextUptime
  • xAI$2.00 in·$6.00 out·500k·99.5% up

Per million tokens. Prices and uptime via OpenRouter, checked 29 Sep 2026.

Common questions

What is the difference between Claude Sonnet 5.5 and Grok 4.5?

Claude Sonnet 5.5 is developed by Anthropic while Grok 4.5 is developed by xAI. Claude Sonnet 5.5 has a 1.0M token context window vs Grok 4.5's 500K. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 5.5 or Grok 4.5?

It depends on your use case. Claude Sonnet 5.5 and Grok 4.5 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 54 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 5.5 cost compared to Grok 4.5?

Claude Sonnet 5.5 costs $2/M input tokens and Grok 4.5 costs $2/M input tokens. Grok 4.5 is $0.00/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 Claude Sonnet 5.5 and Grok 4.5 on Rival?

This page shows a side-by-side comparison of Claude Sonnet 5.5 and Grok 4.5 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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