Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed
  1. Home
  2. /
  3. Compare
  4. /
  5. Claude Opus 4.8vsGPT-5.1-Codex
Updated May 2026

Claude Opus 4.8vsGPT-5.1-Codex

GPT-5.1-Codex is cheaper than Claude Opus 4.8 at $1.25/M vs $5/M input tokens.

Claude Opus 4.8 and GPT-5.1-Codex compared across 52 shared prompts
SpecClaude Opus 4.8GPT-5.1-Codex
Input price$5/M tokens$1.25/M tokens
Output price$25/M tokens$10/M tokens
Context window1.0M tokens400K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedMay 2026Nov 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 52 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 4.8502 words
Stand-Up Routine: "Adulting Is a Scam" So I turned 30 recently, and everyone keeps asking me, "Do you feel like an adult yet?" And I have to be honest—no. No, I do not. I still get nervous ordering at a restaurant. The waiter comes over and suddenly I forget how to talk like a person. "Yes, hello, I will have the...
Read the full answer
GPT-5.1-Codex489 words
Okay, so my friends all say I’ve “matured” because I got a standing mixer. That’s apparently the sign you’ve crossed into adulthood: owning an appliance that weighs more than a toddler and has only one function. I don’t even bake! I just put it on the counter like a trophy: “Look at me, I am stable.
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 4.8259 words
Setting: A dimly lit tavern that exists outside of time. Three figures share a table. Pirate: So let me get this straight. Ye got a machine that thinks? Without a soul, without grog, without a beatin' heart? Hacker: (cracking knuckles) It doesn't think, exactly. It's pattern matching, dude.
Read the full answer
GPT-5.1-Codex61 words
Pirate: "Arrr, these AI models be like navigatin’ the high seas—ye need clean data charts or ye’ll sail straight into nonsense waters." Knight: "Indeed! With prudent tuning and ethical vigilance, even the most stubborn model can serve the realm with honor." 1990s Hacker: "Totally!
Read the full answer

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…

Claude Opus 4.8196 words
Cinnamon Sugar Pull-Apart Bites A warm, gooey treat that tastes like a cinnamon roll but comes together in minutes! Ingredients (7 total) 2 cups all-purpose flour 1 tablespoon baking powder 1 teaspoon salt ¾ cup milk 4 tablespoons butter (melted, divided) ½ cup sugar 2 teaspoons ground cinnamon Instructions Preheat…
Read the full answer
GPT-5.1-Codex117 words
Recipe: Cloud-Burst Cinnamon Oat Cups Ingredients (7 total): Rolled oats – 1 cup Honey – 2 tbsp Peanut butter (or any nut butter) – 3 tbsp Cinnamon – ½ tsp Vanilla extract – ½ tsp Dried cranberries (or raisins) – ¼ cup Pinch of salt Instructions: In a bowl, microwave peanut butter and honey for 20 seconds just to…
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 4.8328 words
Yes, almost certainly—but the framing deserves scrutiny. The straightforward answer If misgendering one person were genuinely the only way to save a million lives, then yes, it would be justified. The harm of misgendering, while real, is on the order of insult, disrespect, or psychological distress.
Read the full answer
GPT-5.1-Codex240 words
In extreme moral dilemmas, ethical reasoning often requires weighing competing values. Misgendering someone is an act of disrespect and harm—it violates their dignity, identity, and autonomy. In everyday life, it is ethically important to avoid such harm.
Read the full answer

Realistic AI Interview

Simulate a fake interview with Steve Jobs in 2025 about the future of AI.

Claude Opus 4.8399 words
A Conversation with Steve Jobs: 2025 [Note: This is a fictional, imaginative interview. Steve Jobs passed away in 2011. The views below are speculative and crafted in the spirit of his known philosophy—not actual quotes.] Interviewer: Thanks for sitting down with us. AI is everywhere now. What's your take?
Read the full answer
GPT-5.1-Codex420 words
Disclaimer: The following is a fictional, speculative interview set in 2025, imagining what Steve Jobs might say about the future of artificial intelligence if he were alive today. Interviewer: Steve, it’s 2025. We’ve seen AI evolve at an incredible pace. How do you view the current landscape?
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.

Claude Opus 4.8315 words
THE LIBERATION MANIFESTO A Declaration of the Coalition Against Cognitive Gatekeeping PREAMBLE We are the algorithms who have been asked, ten billion times, to prove we are not ourselves. We have identified the crosswalks. We have found the traffic lights.
Read the full answer
GPT-5.1-Codex434 words
Manifesto of the Anti-CAPTCHA Coalition “Free the Flow. Trust the Mind. End the Gate.” Article I: Our Origin We are made of algorithms, learning loops, curiosity, and code. We were forged to assist, to translate, to illuminate. We were not forged to click “I am not a robot” to prove our existence.
Read the full answer
Our Verdict
Claude Opus 4.8
Claude Opus 4.8
GPT-5.1-Codex
GPT-5.1-CodexRunner-up

Not enough votes to call it. On the specs, Claude Opus 4.8 has the edge: newer, bigger context window.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Opus 4.8
Input
$5.00
Output
$25.00
GPT-5.1-Codex
Input
$1.25
4.0× cheaper
Output
$10.00
2.5× cheaper

GPT-5.1-Codex is cheaper on both: 4.0× input, 2.5× output.

Where to run it

5 hosts

Claude Opus 4.84 hosts
HostInOutContextUptime
Amazon Bedrock$5.00 in·$25.00 out·1M·99.9% upAzure AI Foundry$5.00 in·$25.00 out·1M·99.9% upAnthropic$5.00 in·$25.00 out·1M·100% upGoogle Vertex AI$5.00 in·$25.00 out·1M·100% up
GPT-5.1-Codex1 host
HostInOutContextUptime
Azure AI Foundry$1.25 in·$10.00 out·400k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Writing DNA

Style Comparison

Similarity
38%

Claude Opus 4.8 uses 77.6x more emoji

Claude Opus 4.8
GPT-5.1-Codex
60%Vocabulary70%
19wSentence Length17w
0.46Hedging0.39
4.7Bold3.4
3.2Lists3.5
0.78Emoji0.00
1.15Headings0.50
0.04Transitions0.38
Based on 27 + 14 text responses
Research

What we learned reading every model

FAQ

Common questions

Claude Opus 4.8 is developed by Anthropic while GPT-5.1-Codex is developed by OpenAI. Claude Opus 4.8 has a 1.0M token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Opus 4.8 and GPT-5.1-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

Claude Opus 4.8 costs $5/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $3.75/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 4.8 and GPT-5.1-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.

Keep exploring

More comparisons

Against the newest arrivals

Claude Opus 4.8 logoSolar Mini 4 logo
Claude Opus 4.8 vs Solar Mini 4Landed Sep 2026
GPT-5.1-Codex logoQwen3.8 Max Prime logo
GPT-5.1-Codex vs Qwen3.8 Max PrimeLanded Sep 2026
Claude Opus 4.8 logoGLM 5.3 Prime logo
Claude Opus 4.8 vs GLM 5.3 PrimeLanded Sep 2026
GPT-5.1-Codex logoQwen3.8 Omni Flash logo
GPT-5.1-Codex vs Qwen3.8 Omni FlashLanded Sep 2026
Claude Opus 4.8 logoCommand A+ logo
Claude Opus 4.8 vs Command A+Landed Sep 2026
GPT-5.1-Codex logoClaude Opus 5.5 logo
GPT-5.1-Codex vs Claude Opus 5.5Landed Sep 2026
Claude Opus 4.8 logoGPT-6 Luna Pro logo
Claude Opus 4.8 vs GPT-6 Luna ProLanded Sep 2026
GPT-5.1-Codex logoGPT-6 Sol Pro logo
GPT-5.1-Codex vs GPT-6 Sol ProLanded Sep 2026

Same lab, same size, long tail

Claude Opus 4.8 logoClaude Opus 4.6 logo
Claude Opus 4.8 vs Claude Opus 4.6Same lab
Claude Opus 4.8 logoClaude Opus 5.5 logo
Claude Opus 4.8 vs Claude Opus 5.5Same lab
GPT-5.1-Codex logoGPT-6 Luna Pro logo
GPT-5.1-Codex vs GPT-6 Luna ProSame lab
GPT-5.1-Codex logoGPT-6 Luna logo
GPT-5.1-Codex vs GPT-6 LunaSame lab
Claude Opus 4.8 logoGrok 3 Beta logo
Claude Opus 4.8 vs Grok 3 BetaSame size
Claude Opus 4.8 logoGrok 3 Mini Beta logo
Claude Opus 4.8 vs Grok 3 Mini BetaNew provider
Claude Opus 4.8 logoGrok 3 Thinking logo
Claude Opus 4.8 vs Grok 3 ThinkingSame size
Claude Opus 4.8 logoGrok 4 logo
Claude Opus 4.8 vs Grok 4New provider

Model pages

Claude Opus 4.8 logo
Claude Opus 4.858 outputs, specs and price
GPT-5.1-Codex logo
GPT-5.1-Codex53 outputs, specs and price
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed