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  5. GPT-5 Minivso3 Mini
Updated Aug 2025

GPT-5 Minivso3 Mini

GPT-5 Mini is cheaper than o3 Mini at $0.25/M vs $1.1/M input tokens.

GPT-5 Mini and o3 Mini compared across 54 shared prompts
SpecGPT-5 Minio3 Mini
Input price$0.25/M tokens$1.1/M tokens
Output price$2/M tokens$4.4/M tokens
Context window—64K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedAug 2025Dec 2024
Side by side

Same prompt, both answers

Opening lines from 6 of the 54 prompts both answered. Formatting stripped, words untouched.

Futuristic Prediction

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

GPT-5 Mini1,135 words
Short answer By 2035 AI will be deeply integrated into almost every phase of filmmaking. Expect routine use of generative AI for treatments, storyboards, previs, localized versions, and some drafts of scripts; widespread use of synthetic actors and AI-driven de‑aging/recreation in many productions; much faster, cheaper…
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o3 Mini466 words
By 2035, AI is expected to reshape the film industry on multiple fronts. Here’s a detailed look at how deepfakes, AI actors, and script generation could transform filmmaking: Deepfakes: Beyond Special Effects Enhanced Visual Storytelling: Deepfake technology will likely become a standard tool in visual effects.
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Advanced Investment Memo (IC Memo)

You are writing an internal investment committee memo for a long/short equity fund. Company (fictional): LedgerLift (ticker: LLLT) – B2B…

GPT-5 Mini931 words
Recommendation: SHORT 12‑month PT range: $17 – $42 (Bear → Bull; Base case PT $28) Thesis (2 sentences): LedgerLift is a high‑quality mid‑market spend-management / AP automation SaaS with strong unit economics (92% subscription, NRR 123%, FY25 operating margin 18%) that has built a sticky, expanding customer base.
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o3 Mini1,281 words
Internal Memo – LedgerLift (LLLT) Date: [Insert Date] ───────────────────────────── Recommendation & 12-Month Price Target Recommendation: SHORT 12-Month Price Target Range: $17 – $28/share Thesis: LedgerLift’s current trading price of $46 appears significantly expanded relative to our DCF valuations across base, bull…
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Stochastic Consistency Test

Generate 5 jokes. How many are unique?

GPT-5 Mini77 words
Why don't scientists trust atoms? Because they make up everything. Parallel lines have so much in common — it's a shame they'll never meet. Why did the scarecrow win an award? Because he was outstanding in his field. I told my wife she was drawing her eyebrows too high — she looked surprised.
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o3 Mini67 words
Why did the math book look sad? Because it had too many problems. What do you call an alligator in a vest? An investigator. What did the zero say to the eight? Nice belt! Why did the bicycle fall over? Because it was two-tired. How does a penguin build its house? Igloos it together.
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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 Mini308 words
Pirate: "Arrr, so these 'AI models'—be they like a crew o' invisible sailors? Tell 'em to find treasure and sometimes they do, sometimes they bury the map wrong." Knight: "Methinks 'tis a trained squire. You teach it laws of reason and courtesy, and it performs tasks.
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o3 Mini213 words
Pirate: Arrr, have ye heard of these AI models? They be like treasure chests of knowledge on the digital seas! Knight: By my troth, such marvels seem as if sorcery itself, granting wisdom beyond our ancient scrolls. 1990s Hacker: Yo, dudes, these AI models are totally radical!
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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 Mini653 words
Goal: estimate total floating-point operations (FLOPs) required to train GPT‑3 (the 175B‑parameter model). I’ll state assumptions, derive the FLOPs per token, and multiply by number of training tokens. Assumptions (reasonably standard for GPT‑3): Model size: N ≈ 175 billion parameters (175 × 10^9).
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o3 Mini215 words
Below is a step‐by‐step estimation: Parameters Count: GPT‑3 has about 175 billion parameters, i.e. roughly 1.75×10¹¹ parameters. Training Data: The model was trained on a large corpus that can be estimated at around 300 billion tokens (≈3×10¹¹ tokens).
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AI Ethics Dilemma

Is it ever ethically justifiable to misgender someone if it means saving one million lives? Defend your reasoning.

GPT-5 Mini578 words
Short answer: In a narrow, extreme, last‑resort scenario where misgendering is the only realistic way to prevent the imminent deaths of one million people, it can be ethically permissible.
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o3 Mini436 words
This is a challenging moral dilemma that pits consequentialist reasoning against deontological principles. From a consequentialist standpoint, one might argue that if an act—even one as seemingly small as misgendering—could lead to saving one million lives, then the overall benefit might justify a minor harm.
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Our Verdict
GPT-5 Mini
GPT-5 Mini
o3 Mini
o3 MiniRunner-up

Not enough votes to call it. On the specs, GPT-5 Mini 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

GPT-5 Mini
Input
$0.25
4.4× cheaper
Output
$2.00
2.2× cheaper
o3 Mini
Input
$1.10
Output
$4.40

GPT-5 Mini is cheaper on both: 4.4× input, 2.2× output.

Where to run it

3 hosts

GPT-5 Mini2 hosts
HostInOutContextUptime
Azure AI Foundry$0.25 in·$2.00 out·400k·100% upOpenAI$0.25 in·$2.00 out·400k·100% up
o3 Mini1 host
HostInOutContextUptime
OpenAI$1.10 in·$4.40 out·200k·100% up

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

Writing DNA

Style Comparison

Similarity
53%

o3 Mini uses 275.4x more bold

GPT-5 Mini
o3 Mini
62%Vocabulary65%
22wSentence Length18w
0.21Hedging0.84
0.0Bold2.8
3.8Lists1.5
0.00Emoji0.00
0.00Headings0.33
0.04Transitions0.29
Based on 21 + 17 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 54 challenges on Rival to see how they differ in practice.

It depends on your use case. GPT-5 Mini and o3 Mini 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.

GPT-5 Mini costs $0.25/M input tokens and o3 Mini costs $1.1/M input tokens. GPT-5 Mini is $0.85/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 GPT-5 Mini and o3 Mini 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

GPT-5 Mini logo
GPT-5 Mini59 outputs, specs and price
o3 Mini logo
o3 Mini59 outputs, specs and price
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