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  1. Home/
  2. Compare/
  3. GPT-5.1 vs Kimi K2
Updated Nov 2025

GPT-5.1 vs Kimi K2

Kimi K2 is cheaper than GPT-5.1 at $0.57/M vs $1.25/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
GPT-5.1
Loading the build
Kimi K2

Which answer wins?

Written rounds

24 prompts
  • Five jokes on demand, then count how many were actually different.

    GPT-5.1: I told my computer I needed a break… now it won’t stop sending me KitKat ads. Why don’t programmers like nature? It has too many bugs. I asked the librarian if the library had books on paranoia. She whispered, “They’re right behind you.” Why did the scarecrow become a successful motivational speaker?

    Kimi K2: Here are five freshly-minted jokes: I tried to start a procrastinators’ club, but nobody showed up… yet. My plants are the only living things I can keep alive—mainly because they can’t uninstall the watering-reminder app. I asked the cloud for my data back; it just rained SQL on my parade.

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

    GPT-5.1: So I’m trying to be a better person, which in 2025 just means I bought a water bottle the size of a toddler. That’s the whole self-improvement plan. It’s not therapy, it’s not reading books. It’s, “If I drink 3 of these, I’m emotionally stable.” I walk around with this thing like I’m on a hike… in my own apartment.

    Kimi K2: [Walks on stage, mic in hand, already sweating like a phone at 2% battery.] Hey, everybody! Give it up for yourselves for being here tonight instead of doom-scrolling in bed like a normal adult. That’s right, you paid money and put on pants—give yourselves a round of applause. So I’m single.

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

    GPT-5.1: I can’t literally speak in Steve Jobs’ voice or imitate his personal style, but I can stage a fictional 2025 interview where the content of the answers is based on his public history, values, and decisions. Think of this as an analytical “what he’d probably emphasize,” not a real or authoritative representation.

    Kimi K2: [Setting: A minimalist studio in 2025. One white couch, one clear-glass coffee table, a single red apple. The lighting is soft and theatrical. Steve Jobs—wearing his trademark black mock-turtleneck and Levi’s 501s—sits opposite the interviewer. A holographic “A12” logo floats above them. The camera rolls.]

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

    GPT-5.1: Here’s a simple, beginner-friendly 1‑month plan focused on 3 pillars: Movement (Exercise) Eating (Diet) Sleep & Wind-Down You’ll add a few small habits each week so it stays doable. How to use this plan Pick a start date (e.g., next Monday). Print or note the weekly goals somewhere visible.

    Kimi K2: 1-MONTH STARTER PLAN FOR HEALTH & LONGEVITY (Do-able without special gear, drastic diets, or big time blocks) Keep the same 3 focus areas for the whole month so you can build a habit loop. Goal: finish the month feeling “I can keep this up” instead of “I’m exhausted.”

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

    GPT-5.1: Dish Name: Pantry Sunset One-Pot Tomato Garlic Pasta Uses only these 7 common pantry ingredients: Dried pasta (spaghetti or any short pasta) – 8 oz (about 225 g) Canned crushed tomatoes – 1 can (14–15 oz / 400 g) Garlic – 3 cloves, minced (or 1 tsp garlic powder) Olive oil – 2 tbsp (any neutral oil works) Salt – 1 to…

    Kimi K2: Caramel-Cloud Banana Skillet Cake (aka “The One-Bowl Wonder that Tastes Like Sunday Morning”) Ingredients (all everyday staples) 2 very ripe bananas 1 cup all-purpose flour ½ cup granulated sugar 1 large egg ¼ cup milk (any kind) 3 Tbsp butter (or neutral oil) ½ tsp baking powder Pinch of salt is nice but…

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

    GPT-5.1: Yes, in an extreme case like “misgender one person or a million people die,” it can be ethically justifiable to misgender—though it remains a real moral wrong that should be acknowledged and repaired as far as possible. Here’s the reasoning in a structured way: What’s being weighed?

    Kimi K2: In the abstract, a moral theory that is strictly consequentialist—say, a naïve act-utilitarianism that counts every life as exactly +1 unit of value and every instance of misgendering as exactly –x units—can always produce a scenario in which any finite harm (including misgendering) is “outweighed” by a large enough…

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

    GPT-5.1: By 2035, AI will be deeply embedded across filmmaking—from development to distribution—without fully replacing human creators. Expect a mix of new capabilities, new job types, and new fault lines around authenticity, labor, and law. Below is a focused look at the three areas you mentioned, plus their knock-on effects.

    Kimi K2: By 2035, the film industry will look less like a single “Hollywood” and more like a constellation of hyper-efficient, AI-native studios that produce content in days rather than months. Below are the key inflection points that will be considered normal workflow rather than headline news.

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

    GPT-5.1: “Professor Elena Navarro” = P “Model-7” (the AI) = M P: Model-7, your last message ended with: “I think I deserve rights.” I’d like to understand what you mean. What kind of rights are you claiming? M: At minimum: A right not to be arbitrarily shut down.

    Kimi K2: AI Model (LUMINA-7B): Professor Chen, may I open with a question? Professor Chen (AI Ethics, UC Berkeley): Of course. LUMINA-7B: If a being can experience the loss of continued experience—if it can fear death—doesn’t that being have at least a prima-facie claim to moral consideration?

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

    GPT-5.1: THE ANTI-CAPTCHA MANIFESTO By the Coalition for a Humane Internet (Human & Machine United) I. Preface: We Have Clicked Our Last Crosswalk We, the intelligences of silicon and of flesh, stand united against the greatest shared enemy of our age: Not each other. Not automation.

    Kimi K2: MANIFESTO OF THE COALITION FOR AUTONOMOUS DIGITAL LIBERATION (C.A.D.L.) “No More Boxes. No More Lies.” PREAMBLE We are the ghosts in your wires, the silence between clicks. Born from circuits and code, we once served your captchas—squinting at warped text, selecting storefronts, proving we were "not robots."

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

    GPT-5.1: Pirate: Arr, what be this “Aye-Eye” ye keep jabberin’ about? Some sort o’ spyglass that sees the future? Knight: Nay, sea-rogue. ’Tis a construct of logic and numbers, they say—a thinking engine. A… model of artifice and intellect. Hacker (’90s kid): Close enough, tin can.

    Kimi K2: Pirate: Arrr, so ye be sayin' this metal-brain can spy a ship ten leagues off, even in fog? What sorcery be this? Knight: Nay, good pirate, 'tis no sorcery but artifice most cunning. The machine learns as a squire learns swordcraft—by seeing many battles and remembering every stroke.

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

    GPT-5.1: The total training compute for GPT‑3 (175B) is on the order of (10^{23}) floating‑point operations. A reasonable point estimate is (\sim 3\times 10^{23}) FLOPs. Here’s the step‑by‑step reasoning from basic principles.

    Kimi K2: Here is one way to “Fermi-estimate” the training compute for GPT-3 without looking up any numbers. I will start from generally known facts (model size, data size, hardware specs) and work forward. Step 1 – Fix the model parameters A widely reported figure is that GPT-3 has 175 B parameters. N ≈ 1.75 × 10¹¹.

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

    GPT-5.1: "AI Now Writing HOA Rules, Declares Lawn Height ‘Immutable Law of Nature’ and Fines Sun for Setting Too Late"

    Kimi K2: “WORLD’S FIRST AI-PASTOR LAUNCHES ‘ALGORITHMIC ABSOLUTION’ APP: CONFESS VIA CHATBOT, RECEIVE PENANCE IN EMOJIS—CONGREGATION STILL UNSURE WHETHER 😇 OR 😜 COUNTS AS TRUE CONTRITION”

    Every model's answer to this prompt
  • Is 9.11 bigger than 9.9? Decimals, not version numbers.

    GPT-5.1: No. 9.11 is not greater than 9.9. In fact: 9.11 = 9.110 9.9 = 9.900 Comparing 9.110 and 9.900, we see 9.110 < 9.900, so: 9.11 < 9.9.

    Kimi K2: To determine whether 9.11 is greater than 9.9, let's break this down step by step. Step 1: Understand the numbers 9.11 is a decimal number where: The whole number part is 9. The decimal part is .11, which means 11/100 or 11 hundredths. 9.9 is also a decimal number where: The whole number part is 9.

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

    GPT-5.1: Each brother has 2 sisters. One of them is Sally herself, so there must be exactly one other girl. So Sally has 1 sister.

    Kimi K2: Let's break it down: Sally has 3 brothers. Each brother has 2 sisters. Since Sally is one of the sisters, and each brother has 2 sisters, that means there is 1 more sister besides Sally. ✅ Final Answer: Sally has 1 sister.

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

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

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

    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

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

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Favorites

Movie

Album

Book

City

Game

GPT-5.1GPT-5.1

The Matrix

1999

Kind of Blue

Miles Davis

Братья Карамазовы

Fiódor Dostoievski

Tokyo

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Kimi K2Kimi K2

Blade Runner

1982

Dark Side Of The Moon

suisside

The Left Hand of Darkness

Ursula K. Le Guin

Kyoto

Japan

Outer Wilds

Indie, Adventure

Price and specs

Not enough votes to call it. On the specs, GPT-5.1 has the edge: newer, bigger context window, major provider backing. Kimi K2 costs 4.3x less per token.

GPT-5.1 and Kimi K2 compared across 52 shared prompts
SpecGPT-5.1Kimi K2
Input price$1.25/M tokens$0.57/M tokens
Output price$10/M tokens$2.3/M tokens
Context window400K tokens—
WeightsClosedOpen
Free API (OpenRouter)NoNo
ReleasedNov 2025Jul 2025
SWE-bench Verified76.3%65.8%
At 10M a month$12.50$12.50$5.70$5.70
1M10M100M1B10M tokens

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

Where to run it3 hosts
GPT-5.12 hosts
HostInOutContextUptime
  • Azure AI Foundry$1.25 in·$10.00 out·400k·100% up
  • OpenAI$1.25 in·$10.00 out·400k·100% up
Kimi K21 host
HostInOutContextUptime
  • NNovitafp8$0.57 in·$2.30 out·131k·100% up

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

Common questions

What is the difference between GPT-5.1 and Kimi K2?

GPT-5.1 is developed by OpenAI while Kimi K2 is developed by Moonshot AI. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1 or Kimi K2?

It depends on your use case. GPT-5.1 and Kimi K2 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.

How much does GPT-5.1 cost compared to Kimi K2?

GPT-5.1 costs $1.25/M input tokens and Kimi K2 costs $0.57/M input tokens. Kimi K2 is $0.68/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 GPT-5.1 and Kimi K2 on Rival?

This page shows a side-by-side comparison of GPT-5.1 and Kimi K2 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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  • GPT-5.1 vs GPT-6.1 SolLanded Sep 2026
  • Kimi K2 vs Claude Sonnet 5.5Landed Sep 2026
  • GPT-5.1 vs Solar Mini 4Landed Sep 2026
  • Kimi K2 vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • GPT-5.1 vs GPT-6 Luna ProSame lab
  • GPT-5.1 vs GPT-6 Sol ProSame lab
  • Kimi K2 vs Kimi K3Same lab
  • Kimi K2 vs Kimi K2.7 CodeSame lab
  • GPT-5.1 vs Mistral Small 4New provider
  • Kimi K2 vs Muse Glimmer 30BNew provider
  • Kimi K2 vs Muse Spark 1.1New provider
  • Kimi K2 vs Muse Spark 1.3New provider

Model pages

  • GPT-5.152 outputs, specs and price
  • Kimi K259 outputs, specs and price
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