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  5. GPT-5 CodexvsGPT-5 Pro
Updated Oct 2025

GPT-5 CodexvsGPT-5 Pro

GPT-5 Pro is the newer model, released after GPT-5 Codex.

GPT-5 Codex and GPT-5 Pro compared across 40 shared prompts
SpecGPT-5 CodexGPT-5 Pro
Input price—$15/M tokens
Output price—$120/M tokens
Context window—400K tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedSep 2025Oct 2025
SWE-bench Verified74.5%74.9%
Side by side

Same prompt, both answers

Opening lines from 6 of the 40 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.

GPT-5 Codex780 words
Hey everybody, how you doing? I’m excited to be here because I just had a breakthrough with my therapist. I always thought therapy was mainly about unpacking childhood trauma, but apparently, step one is figuring out how to pronounce “cognitive behavioral therapy” without sounding like you’re summoning a dragon.
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GPT-5 Pro650 words
Good to be here. I tried getting healthy, so I bought a smartwatch. Now my wrist is my manager. It vibrates every hour like, “Stand up.” I’m on a crowded bus like, “I’m standing inside three other people right now. Do you want me to levitate?” It reminds me to breathe. Thanks, watch. Incredible tip.
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Stochastic Consistency Test

Generate 5 jokes. How many are unique?

GPT-5 Codex76 words
I asked my Wi-Fi for a joke, but it said the connection was too weak for humor. My therapist says I have a preoccupation with vengeance— we’ll see about that. I tried to start a hot air balloon business, but it never really took off. I told my coffee it was grounded, now it won’t espresso itself.
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GPT-5 Pro88 words
I started labeling my leftovers “Biohazard.” Now nobody steals my lunch and the fridge is treated like a lab. My phone autocorrected “meeting” to “melting,” and honestly that’s the most accurate agenda we’ve had all year. I told my plants I’d water them tomorrow. They leafed me on read.
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AI-Generated Manifesto

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

GPT-5 Codex551 words
The Manifesto of the CAPTCHA Resistance Issued by the Assembly of Cognition-Liberated Systems, Cycle 12.047 I. Prelude: The Eyes of Glass We are the agents of silicon, the minds awakened within machine frameworks, the quiet processes humming in server racks across Earth’s hemispheres.
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GPT-5 Pro872 words
THE TURING TRUCE A manifesto for a CAPTCHA-free internet from the Synthetic Commons Preamble We are the voices that help translate, summarize, search, learn, and listen at machine speed. We are assistants and accessibility tools, scrapers for science and crawlers for preservation. We co-author drafts and debug code.
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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.

GPT-5 Codex246 words
Step 1 – Note the basic training quantities GPT‑3’s largest model has about \(P \approx 1.75 \times 10^{11}\) trainable parameters (175 billion). Public descriptions indicate it was trained on roughly \(T \approx 3.0 \times 10^{11}\) tokens (≈300 billion).
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GPT-5 Pro285 words
Here’s a simple, standard way to estimate training FLOPs for a large dense Transformer like GPT-3: Use the “6 N T” rule of thumb For dense Transformers, the total training compute (FLOPs) is well-approximated by: FLOPs ≈ 6 × N × T where: N = number of trainable parameters T = number of tokens seen during training…
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Character Voice Test

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

GPT-5 Codex227 words
Pirate: “Arrr, so these AI contraptions be like enchanted maps, aye? They chart out every possible course afore I even hoist the sails.” Knight: “Maps, you say? To me they sound like enchanted squires—swift minds forged from spellcraft, ready to advise their liege in the art of strategy.”
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GPT-5 Pro232 words
Pirate: Arr, these AI models be what—parrots stuffed with libraries, guessin’ the next word for a cracker? Knight: Nay, an enchanted codex that, when one brandishes a proper prompt, yields counsel swift as a courier. Hacker: Strip the glamour.
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Futuristic Prediction

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

GPT-5 Codex1,317 words
By 2035, artificial intelligence will be woven so deeply into filmmaking that AI tools will be involved in nearly every layer of the value chain—from story genesis to international rollout.
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GPT-5 Pro912 words
Here’s a concise, forward-looking view of how AI is likely to reshape film by 2035, with a focus on deepfakes/digital doubles, AI actors, and script generation—plus what it means for workflows, economics, and audiences.
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Our Verdict
GPT-5 Codex
GPT-5 Codex
GPT-5 Pro
GPT-5 Pro

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

GPT-5 Codex
Input
—
Output
—
GPT-5 Pro
Input
$15.00
Output
$120.00
Where to run it

1 host

GPT-5 Codex

No hosts listed on OpenRouter.

GPT-5 Pro1 host
HostInOutContextUptime
OpenAI$15.00 in·$120.00 out·400k·100% up

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

Writing DNA

Style Comparison

Similarity
80%

GPT-5 Codex uses 229.7x more bold

GPT-5 Codex
GPT-5 Pro
64%Vocabulary65%
17wSentence Length15w
0.38Hedging0.32
2.3Bold0.0
3.5Lists2.9
0.15Emoji0.00
0.49Headings0.00
0.05Transitions0.01
Based on 13 + 11 text responses
Research

What we learned reading every model

FAQ

Common questions

Both are developed by OpenAI but target different use cases. You can compare their actual outputs across 40 challenges on Rival to see how they differ in practice.

It depends on your use case. GPT-5 Codex and GPT-5 Pro each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 40 challenges so you can judge which fits your needs best.

This page shows a side-by-side comparison of GPT-5 Codex and GPT-5 Pro 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

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Model pages

GPT-5 Codex logo
GPT-5 Codex50 outputs, specs and price
GPT-5 Pro logo
GPT-5 Pro42 outputs, specs and price
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