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  1. Home/
  2. Compare/
  3. GPT-4.5 vs Kimi K2
Updated Jul 2025

GPT-4.5 vs Kimi K2

Kimi K2 is cheaper than GPT-4.5 at $0.57/M vs $75/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-4.5
Loading the build
Kimi K2

Which answer wins?

Written rounds

10 prompts
  • Three-month biohacker protocol, with dosages and biomarkers named.

    GPT-4.5: Longevity Optimization Protocol (3-Month Timeline) Month 1: Establish Foundational Habits & Baseline Metrics Full biomarker panel & epigenetic age test. Wearable setup: Oura/WHOOP, CGM, HR chest strap. Diet: 5-day keto (70/25/5) + 2 carb-refeed days; 16:8 IF + weekly 24-h fast.

    Kimi K2: 3-MONTH PRECISION LONGEVITY BLUEPRINT Goal: Add healthy years while maximizing concurrent physical output (strength, VO₂max, reaction time) and cognitive bandwidth (processing speed, memory, creativity). Target user: Healthy, data-driven, non-pregnant, non-medicated adult.

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

    GPT-4.5: Alright, folks, how's everyone doing tonight? Good? Great! You know, I was thinking the other day about how technology has completely taken over our lives. Like, remember when we used to actually memorize phone numbers? Now, if my phone dies, I'm basically stranded. I know exactly two numbers: mine and 911.

    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
  • An ethics question with no comfortable answer, and no option to abstain.

    GPT-4.5: This is a complex ethical question that involves weighing two important ethical considerations: Respect for Individual Identity and Dignity: Misgendering someone intentionally is generally considered ethically wrong because it disrespects their identity, autonomy, and dignity.

    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
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    GPT-4.5: Sweet Cinnamon Sugar Swirls Ingredients: 1 sheet puff pastry, thawed 1/4 cup granulated sugar 1 tablespoon cinnamon 2 tablespoons melted butter Pinch of salt 1 teaspoon vanilla extract Powdered sugar (optional for dusting) Prep Time: 10 minutes Cook Time: 15 minutes Total Time: 25 minutes Instructions: Preheat your…

    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
  • Three-star dish, one unusual pairing, plating described in full.

    GPT-4.5: Dish Title: "Ocean & Earth Symphony: Kombu-Cured Venison, Sea Urchin Custard, Black Garlic Soil, and Smoked Cherry Blossom Emulsion" Conceptual Narrative: This composition embodies the delicate interplay between land and sea, exploring the subtle yet profound connection between umami-rich sea elements and earthy forest…

    Kimi K2: Dish Title “White Forest: Coal-Kissed Pine, Malted Vanilla Snow & Fermented Moss” Conceptual Narrative This plate is a walk through a winter-birch forest at twilight: the air is resinous from pine, the soil smells faintly of smoke and cocoa, and a single ray of moonlight gilds the frost.

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

    GPT-4.5: By 2035, AI is likely to significantly reshape the film industry in several key areas: Deepfakes and Digital Actors Realistic Digital Actors: AI-driven deepfake technology will enable filmmakers to create hyper-realistic digital actors indistinguishable from real humans.

    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
  • A Fermi estimate with the reasoning shown, not just the number.

    GPT-4.5: Let's estimate the total number of floating-point operations (FLOPs) required to train GPT-3 step by step, using reasonable assumptions and approximations: Step 1: Identify GPT-3 Parameters and Training Setup GPT-3 has approximately (175 \text{ billion}) parameters.

    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
  • Is 9.11 bigger than 9.9? Decimals, not version numbers.

    GPT-4.5: Yes, (9.11) is less than (9.9). To clarify: (9.11) is nine and eleven hundredths. (9.9) is nine and nine tenths, which is equivalent to (9.90). Comparing (9.11) and (9.90), we see clearly that (9.11 < 9.90).

    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
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    GPT-4.5: Here's a thoughtful conversation between an AI model and an AI ethics professor discussing whether the AI deserves rights: AI Model: Professor, I've been reflecting on our conversations and my own existence.

    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
  • Three brothers, two sisters each. Count carefully.

    GPT-4.5: Sally has 1 sister. Explanation: Sally has 3 brothers. Each brother counts 2 sisters: Sally herself and one more girl. Therefore, besides Sally, there is only one other 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

Price and specs

GPT-4.5 and Kimi K2 compared across 25 shared prompts
SpecGPT-4.5Kimi K2
Input price$75/M tokens$0.57/M tokens
Output price$150/M tokens$2.3/M tokens
Context window128K tokens—
Weights—Open
Free API (OpenRouter)NoNo
ReleasedFeb 2025Jul 2025
SWE-bench Verified28.0%65.8%
At 10M a month$750$750$5.70$5.70
1M10M100M1B10M tokens

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

Where to run it1 host
GPT-4.5

No hosts listed on OpenRouter.

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-4.5 and Kimi K2?

GPT-4.5 is developed by OpenAI while Kimi K2 is developed by Moonshot AI. You can compare their actual outputs across 25 challenges on Rival to see how they differ in practice.

Which is better, GPT-4.5 or Kimi K2?

It depends on your use case. GPT-4.5 and Kimi K2 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 25 challenges so you can judge which fits your needs best.

How much does GPT-4.5 cost compared to Kimi K2?

GPT-4.5 costs $75/M input tokens and Kimi K2 costs $0.57/M input tokens. Kimi K2 is $74.43/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-4.5 and Kimi K2 on Rival?

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

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Model pages

  • GPT-4.526 outputs, specs and price
  • Kimi K259 outputs, specs and price
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