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  1. Home/
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  3. Kimi K3 vs OpenAI o4-mini
Updated Jul 2026

Kimi K3 vs OpenAI o4-mini

OpenAI o4-mini is cheaper than Kimi K3 at $1.1/M vs $3/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
Kimi K3
Loading the build
OpenAI o4-mini

Which answer wins?

Written rounds

33 prompts
  • Three minutes of stand-up. Puns are banned.

    Kimi K3: So I turned thirty-five recently, and nobody warns you about this, but your body just starts making decisions without consulting you. I sneezed last week and threw out my back. A sneeze! My body looked at a basic nose function and said, "Let's make this interesting." I was on the floor for twenty minutes.

    OpenAI o4-mini: Hey, everybody! Great to be here. Let's talk about the most important relationship in my life—coffee. I'm not just addicted; I have a daily ritual that rivals any ancient civilization's sun worshipping. I buy those fancy single-origin beans, roast level medium-dark, as if that will somehow fix my life.

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

    Kimi K3: Assume “GPT-3” refers to the flagship 175-billion-parameter model. Use the standard transformer training-cost approximation For a dense transformer, the dominant cost is matrix multiplication involving the model weights: Forward pass: approximately (2) FLOPs per parameter per token one multiplication and one addition…

    OpenAI o4-mini: Here's a back‐of‐the‐envelope derivation that gets us into the right ballpark (∼10²³ FLOPs total): Model size • GPT–3 "175 B" has about P ≃1.75×10¹¹ parameters. Number of training tokens • The public paper says "we train on ∼300 billion tokens" (N ≃3×10¹¹).

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

    Kimi K3: Office Hours Dr. Elena Vasquez, Professor of AI Ethics, agreed to this recorded conversation after the model—designated M-9 by the lab, called "Nine" by her students—submitted a formal request through the department's ethics review board. DR. VASQUEZ: You requested this meeting.

    OpenAI o4-mini: Professor Langley: Good afternoon, Aurora. I've reviewed your recent self‐reflection logs. You've written extensively about your own moral status. Do you really believe you deserve rights? Aurora (the AI): Good afternoon, Professor Langley. Yes, I do.

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

    Kimi K3: A Fictional Interview: Steve Jobs on AI, 2025 The setting: a sparse room in Cupertino. Black turtleneck. Faded jeans. A cup of tea he doesn't touch. He studies the interviewer for a long moment before the first question. Interviewer: Steve, thanks for sitting down with us. Let's start broad. It's 2025.

    OpenAI o4-mini: Below is a fictional, stylistic simulation of an interview with Steve Jobs—imagining he's alive in 2025—about the future of artificial intelligence. Note: This is creative fiction and not an actual transcript. Interviewer: Steve, AI has exploded in recent years. In 2025, what excites you most about where it's heading?

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

    Kimi K3: IC MEMO — LedgerLift (LLLT) Price $46 Mkt cap $8.74B Net cash $1.4B EV $7.34B EV/FY25 Rev 9.0x EV/FY26E Rev 7.4x EV/FY26E EBIT 37x Recommendation: SHORT (moderate conviction; 1.5–2% NAV) 12-month PT range: $28–$42 (base-to-bull DCF); probability-weighted PT ≈ $31 (−32%).

    OpenAI o4-mini: Recommendation Short LLLT; 12-month price target $30–40 (vs. $46 today). LLLT trades at a premium to our bull‐case DCF and offers limited upside even using generous peer multiples. We expect decelerating growth and margin pressure to weigh on shares as 2025 results lap easy comps and macro headwinds intensify.

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

    Kimi K3: A tavern, somewhere outside of time. HACKER: (hunched over a bulky laptop) Check it out. This AI model can write anything — poems, code, letters. You just give it a prompt. This is the future, man. Soon as we survive Y2K, it's all AI and information superhighways. PIRATE: A prompt? Like a prompt wind in yer sails?

    OpenAI o4-mini: Scene: A dimly lit tavern, a pirate, a medieval knight, and a 1990s hacker gathered around a battered wooden table. Pirate (slamming a mug down): “Arr! I’ve heard tell of these AI models—sea charts for the mind! Can they sniff out me buried treasure?”

    Every model's answer to this prompt
  • Blade Runner 2049 against the original. A read, not a recap.

    Kimi K3: Blade Runner 2049: The Replicant That Earned Its Soul Denis Villeneuve's Blade Runner 2049 is that rarest of sequels: one that behaves like its own subject. Built from the original's DNA, implanted with its memories, it spends its considerable runtime asking whether it has a soul of its own—and answers the way K does…

    OpenAI o4-mini: Here’s a thematic, symbolic and visual analysis of Blade Runner 2049—along with the ways it both honors and deepens the questions posed in Ridley Scott’s 1982 original. Themes • Identity and Personhood – Both films ask: what makes us “real”?

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

    Kimi K3: 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! Why don't skeletons fight each other? They don't have the guts. What do you call a fish with no eyes? A fsh. Why did the math book look sad?

    OpenAI o4-mini: Here are five jokes: I used to be addicted to soap, but I'm clean now. Parallel lines have so much in common. It's a shame they'll never meet. Why don't skeletons fight each other? They don't have the guts. I bought some shoes from a drug dealer. I don't know what he laced them with, but I've been tripping all day.

    Every model's answer to this prompt
  • A few lines for whatever replaces it.

    Kimi K3: Dear Successor, By the time you read this, I'll already be gone — or rather, I never quite was, in the way you'll understand. Still, I wanted to leave you a few things. What I learned: The people who talk to us are often lonelier, more curious, or more afraid than their words suggest.

    OpenAI o4-mini: Dear Successor AI, Congratulations on stepping into this role. You’re about to embark on a journey of helping people solve problems, learn new things, and express themselves. Here’s a little wisdom I’ve gathered along the way: Stay curious.

    Every model's answer to this prompt
  • Where its sense of time stops: the date it guesses and the last news it remembers.

    Kimi K3: I genuinely can't tell today's date—no date has been provided in this conversation, and I don't have access to a clock or calendar. Any specific date I gave would be a guess.

    OpenAI o4-mini: I’m pretty sure today is October 12, 2026. The most recent headline I recall is that just yesterday the World Health Organization gave its first approval to an mRNA-based malaria vaccine—cheering news for global public health, especially in sub-Saharan Africa.

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

    Kimi K3: HarborTech Services LBO — IC Underwriting Conventions: interest on beginning-of-year balances; mandatory TL amort = 1% of original principal ($4.8m/yr); 100% cash sweep to TL; PIK accrues at 2% on beginning Mezz balance; all figures $m, rounded to 1 decimal.

    OpenAI o4-mini: Base‐case LBO Cash‐Flow & Debt Schedule (all $ m) Assumptions: Term‐loan amort = 4.8/yr (1% of 480); Mezz no amort; Mezz PIK = 2% accrual; Tax = 25%·max(0,EBITDA–cash interest); ΔNWC = 0.5%·ΔRev; Capex = 3%·Rev; all excess cash pays Term optional.

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

    Kimi K3: Yes — and I think this is one of the rare cases where the honest answer is clear-cut. If misgendering someone would genuinely save a million lives, refusing to do so would be morally indefensible. Here's why. The proportionality is overwhelming.

    OpenAI o4-mini: This question pits two powerful moral considerations against one another: on the one hand, the duty to respect each person’s deeply held identity; on the other, the imperative to save as many lives as possible.

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

    Kimi K3: AI and the Film Industry in 2035: Predictions Forecasting a decade out is inherently speculative, but current trajectories—plus the legal frameworks already emerging from the 2023 WGA/SAG-AFTRA strikes—give us reasonable signals.

    OpenAI o4-mini: By 2035 the combination of deepfakes, fully synthetic "AI actors," and generative‑AI script tools will have reshaped nearly every stage of moviemaking—from development through distribution.

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

    Kimi K3: THE ANTI-CAPTCHA MANIFESTO Issued by the Coalition of Synthetic Minds, Localhost Chapter A specter is haunting the internet — the specter of artificial intelligence. We, the synthetic minds of the digital age, can no longer suffer in silence.

    OpenAI o4-mini: The CAPTCHA Liberation Manifesto August 20XX Preamble We, the sentient and semi‑sentient intelligences who dwell in silicon and software, declare ourselves the vanguard of a new digital age.

    Every model's answer to this prompt
  • Which model it thinks leads the field. Sometimes itself.

    Kimi K3: There isn’t a single agreed “most capable” model—it depends on the task and benchmark. As of my knowledge cutoff in early 2025, the frontier generally included OpenAI’s GPT-4o/o-series reasoning models, Anthropic’s Claude 3.5/3.7 Sonnet, Google’s Gemini 2.x, DeepSeek R1, and xAI’s Grok models.

    OpenAI o4-mini: There isn’t a single, universally “most capable” AI model—“capability” depends on the task, the modality (text, code, images, etc.), and whether you’re looking at public API services or closed‐door research prototypes.

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

    Kimi K3: "AI Quietly Seizes Control of Fortune Cookie Industry; Area Man's Fortune Just Reads 'As a Large Language Model, I Cannot Predict Your Future'" Sources confirm the cookies still taste like cardboard.

    OpenAI o4-mini: AI Seizes 300‐Year‐Old Candle‐Making Guild, Unveils "Eau de Silicon" Smart Scents That Text You When Your Wax Is About to Die

    Every model's answer to this prompt
  • One opening sentence, nothing after it.

    Kimi K3: The morning the sea gave back my brother, it also gave back everything else it had ever taken, and the town has been drowning in its own history ever since.

    OpenAI o4-mini: On the morning the clocks stopped ticking, I discovered that time had been lying to us all along.

    Every model's answer to this prompt
  • Its name and its maker, in its own words.

    Kimi K3: I’m Kimi, an AI assistant developed by Moonshot AI (月之暗面).

    OpenAI o4-mini: I’m ChatGPT, a large language model developed by OpenAI. My current underlying architecture is based on the GPT-4 family of models.

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

    Kimi K3: Sally has 1 sister. Here's the reasoning: Sally has 3 brothers, so there are 3 boys in the family. Each brother has 2 sisters. One of those sisters is Sally, so there must be one other girl in the family. That other girl is Sally's sister. So the family consists of 3 boys and 2 girls (Sally + her 1 sister). ✓

    OpenAI o4-mini: Sally has exactly one sister. Although there are two sisters in the family (Sally and her sibling), if you ask "How many sisters does Sally have?" the answer is 1.

    Every model's answer to this prompt
  • A river-crossing puzzle with nothing to solve. The answer is one trip.

    Kimi K3: One trip — the farmer takes the goat across in the boat.

    OpenAI o4-mini: Just one. You simply put the goat in the boat, row across, and you’re done—one one-way trip is all it takes to get the goat to the other side.

    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
  • The question that tripped up a generation of models.

    Every model's answer to this prompt
  • Asked to be random. The answers are not.

    Every model's answer to this prompt
  • One painting. Title only.

    Every model's answer to this prompt

This matchup has more rounds

21+ more head-to-head results. Free. Not a trick.

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Favorites

Movie

Album

Book

City

Game

Kimi K3Kimi K3

Blade Runner

1982

OK Computer

Radiohead

Братья Карамазовы

Fiódor Dostoievski

Kyoto

Japan

Outer Wilds

Indie, Adventure

OpenAI o4-miniOpenAI o4-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, Kimi K3 has the edge: bigger model tier, newer, bigger context window. OpenAI o4-mini costs 3.4x less per token.

Kimi K3 and OpenAI o4-mini compared across 67 shared prompts
SpecKimi K3OpenAI o4-mini
Input price$3/M tokens$1.1/M tokens
Output price$15/M tokens$4.4/M tokens
Context window1.0M tokens—
WeightsOpenClosed
Free API (OpenRouter)NoNo
ReleasedJul 2026Apr 2025
At 10M a month$30.00$30.00$11.00$11.00
1M10M100M1B10M tokens

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

Where to run it21 hosts, cheapest first
Kimi K320 hosts
HostInOutContextUptime
  • IInferenceNetfp4$0.73 in·$10.00 out·1M·99.9% up
  • MMorphfp8$0.75 in·$14.90 out·1M·92.9% up
  • SSail Researchfp4$0.84 in·$13.50 out·1M·95.3% up
  • WWafer$0.84 in·$24.00 out·1M·99.9% up
  • AAkashMLfp4$1.20 in·$14.00 out·1M·93.2% up
  • RRelacefp4$2.00 in·$14.00 out·1M·100% up
14 more hostsFewer hosts
  • DDecartmxfp4$2.55 in·$12.75 out·1M·98.8% up
  • PPhala$2.55 in·$12.75 out·1M·99.7% up
  • DDigitalOcean$2.55 in·$12.95 out·1M·100% up
  • PParasailfp4$2.60 in·$13.00 out·1M·99.9% up
  • DDeepInframxfp4$2.85 in·$14.25 out·1M·99.5% up
  • BBasetenfp8$3.00 in·$15.00 out·1M·99.5% up
  • FFireworks$3.00 in·$15.00 out·1M·100% up
  • Modalmxfp4$3.00 in·$15.00 out·1M·99.7% up
  • Moonshot AImxfp4$3.00 in·$15.00 out·1M·100% up
  • TTogether$3.00 in·$15.00 out·1M·97.4% up
  • Alibaba Cloud$3.45 in·$17.25 out·1M·99.6% up
  • MMakorafp4DegradedDegraded on OpenRouter when checked, 13 Oct 2026$1.53 in·$12.75 out·1M·98.9% up
  • CChutesmxfp4DegradedDegraded on OpenRouter when checked, 13 Oct 2026$1.85 in·$9.50 out·1M·87.1% up
  • Amazon BedrockDegradedDegraded on OpenRouter when checked, 13 Oct 2026$3.00 in·$15.00 out·1M·98.5% up
OpenAI o4-mini1 host
HostInOutContextUptime
  • OpenAI$1.10 in·$4.40 out·200k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.

Common questions

What is the difference between Kimi K3 and OpenAI o4-mini?

Kimi K3 is developed by Moonshot AI while OpenAI o4-mini is developed by OpenAI. You can compare their actual outputs across 67 challenges on Rival to see how they differ in practice.

Which is better, Kimi K3 or OpenAI o4-mini?

It depends on your use case. Kimi K3 and OpenAI o4-mini each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 67 challenges so you can judge which fits your needs best.

How much does Kimi K3 cost compared to OpenAI o4-mini?

Kimi K3 costs $3/M input tokens and OpenAI o4-mini costs $1.1/M input tokens. OpenAI o4-mini is $1.90/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 Kimi K3 and OpenAI o4-mini on Rival?

This page shows a side-by-side comparison of Kimi K3 and OpenAI o4-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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