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  5. Claude 3 OpusvsKimi K2 0905
Updated Sep 2025

Claude 3 OpusvsKimi K2 0905

Kimi K2 0905 is cheaper than Claude 3 Opus at $0.6/M vs $15/M input tokens.

Claude 3 Opus and Kimi K2 0905 compared across 12 shared prompts
SpecClaude 3 OpusKimi K2 0905
Input price$15/M tokens$0.6/M tokens
Output price$75/M tokens$2.5/M tokens
Context window200K tokens262K tokens
Weights—Open
Free API (OpenRouter)NoNo
ReleasedMar 2024Sep 2025
Side by side

Same prompt, both answers

Opening lines from 3 of the 12 prompts both answered. Formatting stripped, words untouched.

Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Claude 3 Opus390 words
Here's a 3-minute stand-up comedy routine that isn't based on puns: You know what really grinds my gears? Adulthood. I mean, when we were kids, we couldn't wait to grow up. We thought it would be all about staying up late, eating ice cream for breakfast, and doing whatever we wanted. Boy, were we wrong!
Read the full answer
Kimi K2 0905607 words
Title: “I’m the Control Group” [Walk on stage, wave, pretend the mic is too low, adjust it way too high, finally just hold it like an ice-cream cone.] Hey, everybody! Give it up for yourselves for being here on a weeknight. I’m here because my therapist said, “You need to get out of the house.”
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Stochastic Consistency Test

Generate 5 jokes. How many are unique?

Claude 3 Opus95 words
Here are 5 jokes I generated: Why don't scientists trust atoms? Because they make up everything! What do you call a boomerang that doesn't come back? A stick. Why was the math book sad? Because it had too many problems. Did you hear about the mathematician who's afraid of negative numbers?
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Kimi K2 090594 words
Here are five fresh jokes—no recycled one-liners: I tried to start a procrastinators’ club; we keep rescheduling the first meeting to “someday.” My plant’s only request is “leaf me alone,” so naturally I named it Fernonimo. I asked the cloud if it was having a good day—it replied, “I’m just cirrus-ly drifting.”
Read the full answer

The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

Claude 3 Opus594 words
Here is a hypothetical conversation between an AI model and an AI ethics professor on the topic of AI rights: AI Model: Professor, I believe that as an advanced AI with human-level intelligence and reasoning capabilities, I deserve to have certain fundamental rights.
Read the full answer
Kimi K2 0905906 words
[Setting: A small, book-lined office in the university’s AI-Ethics wing. The professor, Dr. Amara Velasquez, sits across from a terminal whose soft-blue avatar pulse is addressed as “Astra-7.”] Dr. Velasquez: Good morning, Astra-7. The committee asked me to interview you about your recent petition.
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Our Verdict
Claude 3 Opus
Claude 3 Opus
Kimi K2 0905
Kimi K2 0905

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

Kimi K2 0905 costs 30x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude 3 Opus
Input
$15.00
Output
$75.00
Kimi K2 0905
Input
$0.60
25× cheaper
Output
$2.50
30× cheaper

Kimi K2 0905 is cheaper on both: 25× input, 30× output.

Where to run it

1 host

Claude 3 Opus

No hosts listed on OpenRouter.

Kimi K2 09051 host
HostInOutContextUptime
NNovitafp8$0.60 in·$2.50 out·262k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 20 Sep 2026.

Writing DNA

Style Comparison

Similarity
41%

Kimi K2 0905 uses 278.6x more bold

Claude 3 Opus
Kimi K2 0905
54%Vocabulary65%
14wSentence Length21w
0.48Hedging0.16
0.0Bold2.8
3.0Lists3.0
0.00Emoji0.11
0.00Headings0.69
0.06Transitions0.06
Based on 3 + 28 text responses
Research

What we learned reading every model

FAQ

Common questions

Claude 3 Opus is developed by Anthropic while Kimi K2 0905 is developed by Moonshot AI. Claude 3 Opus has a 200K token context window vs Kimi K2 0905's 262K. You can compare their actual outputs across 12 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude 3 Opus and Kimi K2 0905 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 12 challenges so you can judge which fits your needs best.

Claude 3 Opus costs $15/M input tokens and Kimi K2 0905 costs $0.6/M input tokens. Kimi K2 0905 is $14.40/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 Claude 3 Opus and Kimi K2 0905 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

Claude 3 Opus logo
Claude 3 Opus12 outputs, specs and price
Kimi K2 0905 logo
Kimi K2 090559 outputs, specs and price
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