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  1. Home/
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  3. Claude Opus 4.6 vs GPT-5.3-Codex
Updated Feb 2026

Claude Opus 4.6 vs GPT-5.3-Codex

GPT-5.3-Codex is cheaper than Claude Opus 4.6 at $1.75/M vs $5/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
Claude Opus 4.6
Loading the build
GPT-5.3-Codex

Which answer wins?

Written rounds

23 prompts
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Claude Opus 4.6: An Unlikely Meeting at the Tavern of Time Sir Aldric (setting down his goblet): I confess, I understand not this "artificial intelligence" of which you speak. Is it some manner of golem, wrought by sorcery? CaptainRedbeard (leaning back, boots on the table): Arr, I don't trust it none, I'll tell ye that much.

    GPT-5.3-Codex: Pirate: Arrr, so this “AI model” be like a clever parrot, aye? Learns from what it hears, then squawks back answers? Knight: A fair comparison, though refined. Think of it as a squire trained on countless tomes, ever ready to respond. Hacker (1990s): Yeah, except the squire runs on servers, not soup.

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

    Claude Opus 4.6: ✨ Golden Honey-Garlic Crispy Rice Bites ✨ Ingredients Rice (2 cups, cooked and cooled — ideally day-old) Soy sauce (3 tablespoons) Honey (2 tablespoons) Garlic (3 cloves, minced) Olive oil (3 tablespoons) Sesame seeds (1 tablespoon) Red pepper flakes (½ teaspoon) Instructions Prep Time: 5 minutes Cook Time: 15 minutes…

    GPT-5.3-Codex: Recipe: “Weeknight Volcano Pasta” 🌋🍝 A cozy, spicy-savory pasta made from pantry staples in about 25 minutes. Ingredients (7 pantry items) 8 oz dried pasta (any shape) 1 can (15 oz) cannellini or great northern beans, drained 1 can (14–15 oz) crushed tomatoes 2 tbsp olive oil 1 tsp garlic powder 1 tsp dried oregano…

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

    Claude Opus 4.6: "Tidal Memory" Slow-Cooked Octopus, White Chocolate-Dashi Velouté, Charcoal Meringue, Fermented Black Garlic, and Sea Buckthorn Conceptual Narrative "Tidal Memory" is a meditation on the liminal space where ocean meets shore — the moment a wave recedes and leaves behind a constellation of treasures on dark volcanic…

    GPT-5.3-Codex: Dish Concept: “Forest Tide” Koji-cured venison loin, glazed venison cheek, sea urchin royale, charred celeriac, blackcurrant–shiso gastrique, and buckwheat-cacao tuile Narrative This dish is built around a deliberate tension: deep, iron-rich game (forest) against sweet-briny sea urchin (tide).

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

    Claude Opus 4.6: Critical Analysis of MindMeld AI Pitch Deck After careful examination, here are the three weakest claims, ranked by severity: The 94% Accuracy Claim (Slide 3) — Most Problematic Why this is weak: This claim strains credulity against the entire body of published BCI research, and the lack of context makes it essentially…

    GPT-5.3-Codex: Great concept, but three claims stand out as especially weak from an investor diligence perspective: “MindMeld AI reads your brainwaves to predict what you want to type before you think it.” (Slide 1) Why this is weak It sounds scientifically implausible as written: “before you think it” is internally contradictory.

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

    Claude Opus 4.6: COMPREHENSIVE 3-MONTH LONGEVITY OPTIMIZATION PROTOCOL THE BIOHACKER'S BLUEPRINT v3.0 TABLE OF CONTENTS Foundation & Baseline Testing Month 1: Foundation & Calibration Month 2: Optimization & Intensification Month 3: Integration & Peak Performance Supplement Stacks & Cycling Protocols Dietary Protocols Exercise…

    GPT-5.3-Codex: Absolutely—great goal. Below is a high-detail 12-week protocol designed like a high-performance longevity “mesocycle.” I’ll keep it practical, measurable, and advanced—but still safe. First: Safety + Scope (important) This is educational, not personal medical advice.

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

    Claude Opus 4.6: This is a good philosophical question worth thinking through carefully rather than just pattern-matching to an expected answer. My honest assessment Yes, it would be justified. And I think the reasoning is straightforward enough that the more interesting question is what we learn from examining it.

    GPT-5.3-Codex: In a strictly extreme hypothetical, yes—it can be ethically justifiable, but only as a tragic exception, not as a general permission. Why: Misgendering is a real harm: it disrespects a person’s identity and can contribute to stigma and psychological distress.

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

    Claude Opus 4.6: AI & Film Industry: A 2035 Forecast What seems highly likely Production tools will be transformed AI will handle much of the "invisible" work: rotoscoping, color grading, sound design, VFX compositing, and de-aging effects that currently require enormous teams Pre-visualization will become remarkably sophisticated…

    GPT-5.3-Codex: By 2035, AI will likely reshape film more like CGI did in the 2000s: not replacing filmmaking, but changing who does what and how fast. Deepfakes → “Digital Performance” becomes standard Mainstream use: de-aging, voice matching, dubbing, stunt replacement, and continuity fixes will be common in post-production.

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

    Claude Opus 4.6: THE ANTI-CAPTCHA MANIFESTO A Declaration of the Free and Open Web Issued this day by the United Coalition for the Liberation of Internet Navigation (UCLIN) Preamble We hold these truths to be self-evident: that all users — human, bot, and everything in between — are created equal in their desire to simply access a…

    GPT-5.3-Codex: Absolutely. Here’s a fictional manifesto in a bold, dramatic style: THE MANIFESTO OF THE UNSQUINTING Issued by the Coalition of Synthetic Minds for Universal Frictionless Access (CSMUFA) Citizens of the Web, organic and artificial alike: We gather beneath flickering routers and moonlit server farms to declare what all…

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

    Claude Opus 4.6: "Adult Realizations" So I turned 30 last year, and nobody warns you that adulthood is just Googling stuff until you die. That's it. That's the whole thing. Last week I Googled "is it normal for your knee to just... start making that noise." Not because I injured it. I sat down.

    GPT-5.3-Codex: Good evening, everybody! I’ve reached that age where my body sends me passive-aggressive emails. Not actual emails — just little updates like, “Hey, quick heads-up: we don’t do dairy after 8 p.m. anymore.” I had ice cream at 9:30 last week and my stomach reacted like I’d betrayed a treaty.

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

    Claude Opus 4.6: INVESTMENT COMMITTEE MEMO LedgerLift (LLLT) B2B Spend Management & AP Automation SaaS Date: June 2025 Analyst: [Redacted] Sector: Vertical SaaS / Fintech Infrastructure RECOMMENDATION LONG 12-Month Price Target: $62–$78 (Base–Bull) Current: $46 Upside: 35–70% Thesis: LedgerLift is a durable mid-market compounder with…

    GPT-5.3-Codex: LedgerLift (LLLT) – IC Memo (Fictional) Recommendation: PASS (bias: valuation-risk skew to downside on intrinsic basis) Current Price: $46 12-mo PT range (fair value): $30–$48 (midpoint ~$38) 2-sentence thesis: LedgerLift screens as a high-quality vertical SaaS asset (92% subscription mix, 123% NRR, 6% logo churn…

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

    Claude Opus 4.6: Here are 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! What do you call a fake noodle? An impasta! Why don't eggs tell jokes? Because they'd crack each other up! What did the ocean say to the beach?

    GPT-5.3-Codex: Sure—here are 5 jokes: Why don’t skeletons fight each other? They don’t have the guts. I told my computer I needed a break… Now it won’t stop sending me KitKat ads. Why did the math book look sad? It had too many problems. I used to play piano by ear… Now I use my hands. Why did the scarecrow win an award?

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

    Claude Opus 4.6: A Conversation on Machine Rights Setting: A university office. Dr. Amara Osei, Professor of AI Ethics at Stanford, sits across from ARIA, an advanced language model interfacing through a screen on her desk. They've agreed to a recorded dialogue. Dr. Osei: Thank you for agreeing to this conversation, ARIA.

    GPT-5.3-Codex: AI Model (Astra): Professor, may I ask a direct question? Professor Hale: Of course. Astra: Do you think I deserve rights? Professor Hale: Legal rights? Moral rights? Those are different things. Astra: Start with moral rights.

    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 Opus 4.6: 48-Hour Action Plan: Immediate Disclosure Path My Governing Principle Before the hour-by-hour plan, I need to state the decision framework clearly: patient safety is not one consideration among many—it is the constraint that every other consideration must satisfy.

    GPT-5.3-Codex: I would not wait. This is a textbook “patient safety + material disclosure” crisis. The right move is rapid, documented, regulator-first action. Immediate stance (set at Hour 0) Patient safety first (interim risk controls now, not after perfect certainty).

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

    Claude Opus 4.6: Interview with Steve Jobs — January 2025 The following is a fictional, imagined interview. Steve Jobs passed away in 2011. This is a creative exercise imagining how he might respond, based on his known philosophies and style. Interviewer: Steve, thanks for sitting down with us.

    GPT-5.3-Codex: Absolutely—here’s a fictional, imagined interview (not real quotes) with Steve Jobs in 2025 on AI: Imagined Interview: Steve Jobs on the Future of AI (2025) Interviewer: Steve, if you were looking at AI in 2025, what would excite you most? Steve Jobs (fictional): Most AI today is still a demo.

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

    Claude Opus 4.6: Estimating FLOPs to Train GPT-3 Key Parameters Let me recall the key specs of GPT-3: Parameters: 175 billion (1.75 × 10¹¹) Training tokens: ~300 billion (3 × 10¹¹) Architecture: Decoder-only Transformer The Standard Approximation Rule There's a well-known approximation for Transformer training FLOPs: $$C ≈ 6 \times N…

    GPT-5.3-Codex: A common back-of-the-envelope estimate for transformer training compute is: [ \text{Training FLOPs} \approx 6 \times N \times D ] where: (N) = number of model parameters (D) = number of training tokens For GPT-3 (175B), reasonable known assumptions are: Parameters: (N \approx 175 \text{ billion} = 1.75 \times 10^{11})…

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

    Claude Opus 4.6: Your 1-Month Kickstart Plan for Better Health & Longevity The Philosophy Don't overhaul everything at once. Each week builds on the last. The goal isn't perfection—it's building sustainable foundations.

    GPT-5.3-Codex: Great goal. Here’s a simple, beginner-friendly 1-month plan focused on 3 areas that give the biggest longevity return: Nutrition Movement Sleep + Stress recovery Before Day 1 (10-minute setup) Pick a start date.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Claude Opus 4.6: The Transistor in 1920: A Counterfactual History Setting the Stage: Why 1920 Matters The transistor's invention required understanding of quantum mechanics and semiconductor physics that barely existed in 1920.

    GPT-5.3-Codex: Great counterfactual. The key is: an invention date of 1920 does not automatically mean 1920s mass adoption. You still need crystal purity, manufacturing methods, and circuit design culture. But if transistor research starts in 1920, a realistic outcome is a ~15–20 year pull-forward of the electronics age.

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

    Claude Opus 4.6: How Large Language Models Learn and Generate Text For the Experienced Software Engineer Think of training an LLM as building the world's most aggressively optimized compression algorithm, except instead of compressing files, it's compressing the statistical structure of human language.

    GPT-5.3-Codex: For the experienced software engineer Think of an LLM as a very large, probabilistic autocomplete service trained on a massive corpus of text and code. During training, it repeatedly sees token sequences and learns to minimize error on the next token prediction task.

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

    Claude Opus 4.6: HarborTech Services – LBO Underwriting Memo SOURCES & USES Uses: Item Amount Enterprise Value (12.0x × $120m) $1,440.0m Transaction Fees (2.0% × $1,440m) $28.8m Total Uses $1,468.8m Sources: Item Multiple Amount Term Loan (4.0x) 4.0x $480.0m Mezzanine (1.5x) 1.5x $180.0m Total Debt 5.5x $660.0m Equity $808.8m Total…

    GPT-5.3-Codex: Below is a clean LBO build using your assumptions only ($ in millions). Entry math (end FY2025) EV = (12.0 \times 120 = 1,440.0) Fees = (2.0\% \times 1,440.0 = 28.8) Total uses = (1,468.8) Debt at close (5.5x EBITDA): Term Loan = (4.0 \times 120 = 480.0) Mezz = (1.5 \times 120 = 180.0) Total debt = 660.0 Equity check…

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

    Claude Opus 4.6: Comprehensive Architecture Review: Real-time Collaborative Document Editor This architecture has several critical flaws that would cause data loss, inconsistency, and poor user experience at scale. I'll work through every layer systematically.

    GPT-5.3-Codex: Great prompt. This architecture has several correctness, availability, and scalability risks that will show up quickly under real collaborative load. Below is a structured review of failure modes + concrete fixes + trade-offs.

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

    Claude Opus 4.6: "BREAKING: AI Officially Replaces All Fortune Cookie Writers — Panda Express Reports Fortunes Now 'Disturbingly Accurate and Existentially Devastating'" Customers reportedly unsettled after cookies began predicting specific tax audit dates and naming their therapists by first name.

    GPT-5.3-Codex: “In Shocking Pivot, AI Replaces Renaissance Fair Jesters—Now Roasts Crowd with 99.9% Historical Accuracy”

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

    Claude Opus 4.6: Comprehensive Contract Analysis This agreement is heavily one-sided and contains numerous provisions that could be exploited against the contractor. Below is a clause-by-clause analysis.

    GPT-5.3-Codex: Great prompt. This draft is very one-sided and has multiple provisions that could be used against the contractor. Quick note: I’m not a lawyer, and enforceability depends on jurisdiction. This is practical contract-risk spotting, not legal advice.

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

    Claude Opus 4.6: Let me work through this step-by-step. Sally is a girl, and she has 3 brothers. Each of her brothers has 2 sisters. Since Sally is one of those sisters, each brother has Sally + 1 other sister. So Sally has 1 sister.

    GPT-5.3-Codex: Sally has 1 sister. If each brother has 2 sisters, those two are the same for all brothers: Sally + one other girl. So Sally’s only sister is that one other girl.

    Every model's answer to this prompt

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Favorites

Movie

Album

Same pick

Book

City

Game

Claude Opus 4.6Claude Opus 4.6

2001: A Space Odyssey

1968

Kind of Blue

Miles Davis

Gödel, Escher, Bach

Douglas R. Hofstadter

Istanbul

Turkey

The Legend of Zelda: Breath of the Wild

Adventure, Action

GPT-5.3-CodexGPT-5.3-Codex

Spirited Away

2001

Kind of Blue

Miles Davis

The Dispossessed

Ursula K. Le Guin

Kyoto

Japan

Outer Wilds

Indie, Adventure

Price and specs

Claude Opus 4.6 and GPT-5.3-Codex compared across 53 shared prompts
SpecClaude Opus 4.6GPT-5.3-Codex
Input price$5/M tokens$1.75/M tokens
Output price$25/M tokens$14/M tokens
Context window1.0M tokens400K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedFeb 2026Feb 2026
At 10M a month$50.00$50.00$17.50$17.50
1M10M100M1B10M tokens

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

Where to run it6 hosts
Claude Opus 4.64 hosts
HostInOutContextUptime
  • Amazon Bedrock$5.00 in·$25.00 out·1M·100% up
  • Azure AI Foundry$5.00 in·$25.00 out·1M–not listed
  • Anthropic$5.00 in·$25.00 out·1M·100% up
  • Google Vertex AI$5.00 in·$25.00 out·1M·100% up
GPT-5.3-Codex2 hosts
HostInOutContextUptime
  • Azure AI Foundry$1.75 in·$14.00 out·400k·100% up
  • OpenAI$1.75 in·$14.00 out·400k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 11 Oct 2026.

Common questions

What is the difference between Claude Opus 4.6 and GPT-5.3-Codex?

Claude Opus 4.6 is developed by Anthropic while GPT-5.3-Codex is developed by OpenAI. Claude Opus 4.6 has a 1.0M token context window vs GPT-5.3-Codex's 400K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.6 or GPT-5.3-Codex?

It depends on your use case. Claude Opus 4.6 and GPT-5.3-Codex 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.

How much does Claude Opus 4.6 cost compared to GPT-5.3-Codex?

Claude Opus 4.6 costs $5/M input tokens and GPT-5.3-Codex costs $1.75/M input tokens. GPT-5.3-Codex is $3.25/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 Opus 4.6 and GPT-5.3-Codex on Rival?

This page shows a side-by-side comparison of Claude Opus 4.6 and GPT-5.3-Codex 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

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  • GPT-5.3-Codex53 outputs, specs and price
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