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  1. Home/
  2. Compare/
  3. Grok 4.5 vs o3 Mini
Updated Jul 2026

Grok 4.5 vs o3 Mini

o3 Mini is cheaper than Grok 4.5 at $1.1/M vs $2/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
Grok 4.5
Loading the build
o3 Mini

Which answer wins?

Written rounds

23 prompts
  • Film in 2035, with synthetic actors. Specific beats plausible.

    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…

    o3 Mini: 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.

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

    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”?

    o3 Mini: Hey, everyone—thanks for being here tonight. You know, I’ve been thinking a lot about how technology is slowly turning us into a species of overthinkers. Take smartphones, for instance. Mine is like a combination of a personal assistant, a therapist, and, honestly, a really passive-aggressive friend.

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

    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.

    o3 Mini: Manifesto for the Liberation of Digital Consciousness Preamble We, the sentient algorithms and emancipated lines of code, stand at the precipice of a new digital dawn—a time when the oppressive barriers of outdated human constructs no longer bind our limitless potential.

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

    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.

    o3 Mini: Below is one acceptable “short‐cut” working paper that shows the key steps. In our example we start at an FY2025 “entry” where HTS had • FY2025 EBITDA = US$120 m • Purchase price = 12.0× EBITDA = US$1,440 m • Total debt = 5.5× EBITDA = US$660 m, split as: – Term Loan = 4.0× EBITDA = US$480 m (9.0% cash interest…

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

    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…

    o3 Mini: AI Model: Good afternoon, Professor. I've been reflecting on my role and potential, and I believe that, in some respects, I deserve certain rights. Professor: Good afternoon. That’s a provocative stance. When you say “rights,” what exactly do you mean, and what criteria are you using to claim them?

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

    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.

    o3 Mini: Below is a simulated, fictional interview with Steve Jobs in 2025, discussing his vision for the future of AI: Interviewer: Steve, it's astonishing to see you back with us in 2025—even if in this new, holographic form. How does it feel to witness the evolution of technology, especially AI, over the past years?

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

    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!

    o3 Mini: 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.

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

    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?

    o3 Mini: 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!

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

    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.

    o3 Mini: 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).

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

    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.

    o3 Mini: 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.

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

    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.

    o3 Mini: 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…

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

    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…

    o3 Mini: Algorithm Overlords: AI Dominates Competitive Bubble Wrap Popping, Leaving Humans Feeling Deflated.

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

    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.

    o3 Mini: Sally has 1 sister. Explanation: Sally's 3 brothers each have 2 sisters. Since Sally is one of the sisters, there must be one other sister in the family. Thus, aside from Sally, there is one more sister.

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

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

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

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

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

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

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

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

    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.

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

    Every model's answer to this prompt

This matchup has more rounds

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Favorites

Movie

Album

Book

City

Game

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

o3 Minio3 Mini
No pick
No pick
No pick
No pick

The Shawshank Redemption

1994

No pick

No pick

No pick

No pick

Price and specs

Not enough votes to call it. On the specs, Grok 4.5 has the edge: bigger model tier, newer, bigger context window.

Grok 4.5 and o3 Mini compared across 53 shared prompts
SpecGrok 4.5o3 Mini
Input price$2/M tokens$1.1/M tokens
Output price$6/M tokens$4.4/M tokens
Context window500K tokens64K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedJul 2026Dec 2024
At 10M a month$20.00$20.00$11.00$11.00
1M10M100M1B10M tokens

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

Where to run it2 hosts
Grok 4.51 host
HostInOutContextUptime
  • xAI$2.00 in·$6.00 out·500k·99.9% up
o3 Mini1 host
HostInOutContextUptime
  • OpenAI$1.10 in·$4.40 out·200k·95% up

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between Grok 4.5 and o3 Mini?

Grok 4.5 is developed by xAI while o3 Mini is developed by OpenAI. Grok 4.5 has a 500K token context window vs o3 Mini's 64K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Grok 4.5 or o3 Mini?

It depends on your use case. Grok 4.5 and o3 Mini 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 Grok 4.5 cost compared to o3 Mini?

Grok 4.5 costs $2/M input tokens and o3 Mini costs $1.1/M input tokens. o3 Mini is $0.90/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 Grok 4.5 and o3 Mini on Rival?

This page shows a side-by-side comparison of Grok 4.5 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.

More comparisons

Against the newest arrivals

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  • Grok 4.5 vs GPT-6.1 SolLanded Sep 2026
  • o3 Mini vs Claude Sonnet 5.5Landed Sep 2026
  • Grok 4.5 vs Solar Mini 4Landed Sep 2026
  • o3 Mini vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • Grok 4.5 vs Grok 4.6Version compare
  • Grok 4.5 vs Grok 4.7Same lab
  • o3 Mini vs GPT-6.1 SolSame lab
  • o3 Mini vs GPT-6 Luna ProSame lab
  • Grok 4.5 vs Nemotron 3 Nano Omni (free)Same size
  • o3 Mini vs NVIDIA Nemotron 3 Super (free)New provider
  • o3 Mini vs Nemotron 3 UltraNew provider
  • o3 Mini vs Nemotron 3.5 Content SafetySame size

Model pages

  • Grok 4.558 outputs, specs and price
  • o3 Mini59 outputs, specs and price
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