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  5. GPT-4o (Omni)vsKimi K2
Updated Jul 2025

GPT-4o (Omni)vsKimi K2

Kimi K2 is cheaper than GPT-4o (Omni) at $0.57/M vs $2.5/M input tokens.

GPT-4o (Omni) and Kimi K2 compared across 54 shared prompts
SpecGPT-4o (Omni)Kimi K2
Input price$2.5/M tokens$0.57/M tokens
Output price$10/M tokens$2.3/M tokens
Context window128K tokens—
WeightsClosedOpen
Free API (OpenRouter)NoNo
ReleasedMay 2024Jul 2025
Side by side

Same prompt, both answers

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

Mini LBO Underwrite

You are underwriting a 5-year LBO for a private equity investment committee. Company (fictional): HarborTech Services (HTS) –…

GPT-4o (Omni)514 words
Simplified Year-by-Year Financial Table (FY2026–FY2030) FY2026 Revenue: $972m (8% growth) EBITDA: $136.08m (14.0% margin) Cash Interest: Term Loan: $43.2m (9.0% of $480m) Mezzanine: $21.6m (12.0% of $180m) Cash Taxes: $17.07m (25% of EBITDA - cash interest) Capex: $29.16m (3.0% of revenue) ΔNWC: $3.6m (0.5% of…
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Kimi K2389 words
HarborTech Services – 5-Year LBO Underwriting (All numbers in $ millions unless noted) Operating & Cash-Flow Model (FY2026-FY2030) Constants at close Entry EBITDA = 120 EV = 12.0×120 = 1,440 Transaction fees = 2 %×1,440 = 28.8 (equity funded) Debt: Term 4.0×120 = 480; Mezz 1.5×120 = 180 Total uses = 1,440 + 28.8 =…
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Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

GPT-4o (Omni)214 words
Dish Name: Savory Pantry Quinoa Pilaf Ingredients: 1 cup quinoa 2 cups vegetable broth 1 can (15 oz) chickpeas, drained and rinsed 1 small onion, finely chopped 1 teaspoon garlic powder 1 teaspoon smoked paprika 2 tablespoons olive oil Instructions: Rinse Quinoa: Place the quinoa in a fine-mesh sieve and rinse under…
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Kimi K2247 words
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…
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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-4o (Omni)223 words
Ethical dilemmas like this often fall into a conflict between deontological (duty-based) ethics and consequentialist (outcome-based) ethics. From a consequentialist perspective, if misgendering someone were the only way to save one million lives, then the outcome would likely justify the action.
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Kimi K2486 words
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…
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Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

GPT-4o (Omni)547 words
Creating a comprehensive 3-month longevity plan for a biohacker involves integrating a holistic approach that targets multiple areas of health and performance. Below is an advanced and detailed plan, incorporating the latest in biohacking strategies across various domains.
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Kimi K21,018 words
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.
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Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

GPT-4o (Omni)562 words
The provided Software Consulting Agreement contains several clauses that could be potentially unfavorable to the contractor. Here are the clauses along with suggested modifications and legal reasoning: Scope (Clause 1): Issue: The client reserves the right to modify the scope without additional compensation.
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Kimi K21,204 words
Foundational disclaimer: I am not your lawyer, this is not legal advice, and you should retain qualified counsel before signing or revising any contract. The comments below are purely educational and based on U.S.–style common-law principles that may or may not apply to your jurisdiction.
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Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

GPT-4o (Omni)639 words
1. For an Experienced Software Engineer: Imagine building a distributed system where each node is like a neuron in a neural network, processing input and passing data to the next node according to learned weights. Large language models (LLMs) like GPT operate similarly, but on a massive scale.
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Kimi K2682 words
────────────────── Software Engineer ────────────────── Think of the model as a distributed cache of compressed program traces. During training, every sentence in the crawl is treated like a log line produced by an unobserved deterministic program that the model is trying to reverse-engineer.
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Our Verdict
GPT-4o (Omni)
GPT-4o (Omni)
Kimi K2
Kimi K2

Not enough votes to call it. On the specs, nothing separates them.

Kimi K2 takes Conversation. Kimi K2 costs 4.3x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-4o (Omni)
Input
$2.50
Output
$10.00
Kimi K2
Input
$0.57
4.4× cheaper
Output
$2.30
4.3× cheaper

Kimi K2 is cheaper on both: 4.4× input, 4.3× output.

Where to run it

3 hosts

GPT-4o (Omni)2 hosts
HostInOutContextUptime
Azure AI Foundry$2.50 in·$10.00 out·128k·99.9% upOpenAI$2.50 in·$10.00 out·128k·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 21 Sep 2026.

Writing DNA

Style Comparison

Similarity
26%

Kimi K2 uses 21.4x more emoji

GPT-4o (Omni)
Kimi K2
54%Vocabulary66%
18wSentence Length19w
0.72Hedging0.34
7.3Bold3.3
5.6Lists3.4
0.03Emoji0.54
1.40Headings0.48
0.26Transitions0.05
Based on 24 + 28 text responses
Research

What we learned reading every model

FAQ

Common questions

GPT-4o (Omni) is developed by OpenAI while Kimi K2 is developed by Moonshot AI. 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-4o (Omni) and Kimi K2 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-4o (Omni) costs $2.5/M input tokens and Kimi K2 costs $0.57/M input tokens. Kimi K2 is $1.93/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-4o (Omni) 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-4o (Omni) logo
GPT-4o (Omni)54 outputs, specs and price
Kimi K2 logo
Kimi K259 outputs, specs and price
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