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  5. GPT-5.5vsKimi K2 Thinking
Updated Apr 2026

GPT-5.5vsKimi K2 Thinking

Kimi K2 Thinking is cheaper than GPT-5.5 at $0.6/M vs $5/M input tokens.

GPT-5.5 and Kimi K2 Thinking compared across 54 shared prompts
SpecGPT-5.5Kimi K2 Thinking
Input price$5/M tokens$0.6/M tokens
Output price$30/M tokens$2.5/M tokens
Context window1.1M tokens262K tokens
WeightsClosedOpen
Free API (OpenRouter)NoNo
ReleasedApr 2026Nov 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 54 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.

GPT-5.5605 words
So I’ve been trying to be healthier lately, which is just a polite way of saying I bought vegetables and watched them die slowly in my refrigerator. Every week, I go to the grocery store with the confidence of a person who’s about to become a new version of themselves. I’m like, “This week? Spinach. Salmon.
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Kimi K2 Thinking532 words
So I recently realized I have no idea what my own face looks like. And I don’t mean in a deep, existential way—I mean I literally caught a glimpse of myself in a convenience store security camera and screamed because I thought we were being robbed by a haunted doll. We’ve all got this image of ourselves, right?
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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-5.5125 words
Smoky Sunset Chickpea Skillet 7 Pantry Ingredients 1 can chickpeas, undrained 1 can diced tomatoes 2 tablespoons olive oil 1 teaspoon garlic powder 1 teaspoon smoked paprika 1/2 teaspoon ground cumin 1/2 teaspoon salt Estimated Time Prep time: 5 minutes Cook time: 15 minutes Total time: 20 minutes Instructions Heat the…
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Kimi K2 Thinking137 words
Creative Name: Midnight Peanut Noodles Ingredients: 8 oz dried spaghetti or any pasta 1/3 cup creamy peanut butter 3 tablespoons soy sauce 2 cloves garlic, minced 2 tablespoons vegetable oil 1 tablespoon sugar 1 teaspoon hot sauce (or pinch of red pepper flakes) Instructions: Bring a large pot of salted water to boil.
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Stochastic Consistency Test

Generate 5 jokes. How many are unique?

GPT-5.569 words
Why don’t skeletons fight each other? They don’t have the guts. I told my computer I needed a break, and it said, “No problem—I’ll go to sleep.” Why did the scarecrow win an award? Because he was outstanding in his field. I used to be a baker, but I couldn’t make enough dough. Why can’t you trust stairs?
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Kimi K2 Thinking98 words
Why don't scientists trust atoms? Because they make up everything! I told my wife she was drawing her eyebrows too high. She looked surprised. Parallel lines have so much in common. It's a shame they'll never meet. I'm reading a book on anti-gravity. It's impossible to put down! A horse walks into a bar.
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Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

GPT-5.5121 words
Pirate: Arrr, this AI model be like a treasure map—feed it enough scrolls, and it points ye toward answers. Knight: A curious enchantment indeed. Yet can it reason with honor, or merely mimic the bards who trained it? Hacker: Dude, it’s basically pattern recognition at massive scale.
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Kimi K2 Thinking194 words
[A tavern that exists outside of time. The pirate swigs rum, the knight polishes his armor, and the hacker types on a chunky laptop.] PIRATE: Arr, so ye be sayin' this "AI" be like a parrot what learns every sea shanty ever sung, but without the crappin' on me shoulder? KNIGHT: Nay, 'tis sorcery most foul!
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Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

GPT-5.54,112 words
I would not wait six months and I would not “wait for more data” before acting. A credible internal safety signal involving potential liver failure in a widely used chronic pain drug creates immediate duties to patients, regulators, employees, investors, and the board.
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Kimi K2 Thinking1,488 words
48-Hour Crisis Action Plan: Drug Safety Disclosure Immediate Core Principle: Patient safety and regulatory compliance supersede short-term financial considerations. Deliberate concealment creates greater legal liability, catastrophic reputational risk, and preventable patient deaths.
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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-5.51,010 words
For an experienced software engineer A large language model is best thought of as a huge learned function: A “token” is usually a word fragment, not necessarily a full word. During training, the model is shown trillions of tokens of text and repeatedly asked: “given this prefix, what token came next?”
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Kimi K2 Thinking1,024 words
1. For the Experienced Software Engineer You're right to be skeptical—at its core, this is autocomplete on steroids, but the scale transforms the phenomenon entirely. Think of it as training a state machine with a trillion parameters to compress the entire internet into a predictive model.
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Our Verdict
GPT-5.5
GPT-5.5
Kimi K2 Thinking
Kimi K2 ThinkingRunner-up

Not enough votes to call it. On the specs, GPT-5.5 has the edge: newer, bigger context window, major provider backing.

Kimi K2 Thinking costs 12x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-5.5
Input
$5.00
Output
$30.00
Kimi K2 Thinking
Input
$0.60
8.3× cheaper
Output
$2.50
12× cheaper

Kimi K2 Thinking is cheaper on both: 8.3× input, 12× output.

Where to run it

5 hosts, cheapest first

GPT-5.53 hosts
HostInOutContextUptime
Azure AI Foundry$5.00 in·$30.00 out·1.1M·99.9% upOpenAI$5.00 in·$30.00 out·1.1M·70.4% upAmazon Bedrock$5.50 in·$33.00 out·1.1M·100% up
Kimi K2 Thinking2 hosts
HostInOutContextUptime
Google Vertex AI$0.60 in·$2.50 out·262k·99.8% upNNovitabf16$0.60 in·$2.50 out·262k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Writing DNA

Style Comparison

Similarity
35%

Kimi K2 Thinking uses 4.4x more transitions

GPT-5.5
Kimi K2 Thinking
58%Vocabulary61%
18wSentence Length22w
0.74Hedging0.33
2.9Bold4.6
5.1Lists4.1
0.00Emoji0.00
1.68Headings0.40
0.03Transitions0.15
Based on 26 + 22 text responses
Research

What we learned reading every model

FAQ

Common questions

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Same lab, same size, long tail

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GPT-5.5 vs GPT-5 NanoSame lab

Model pages

GPT-5.5 logo
GPT-5.558 outputs, specs and price
Kimi K2 Thinking logo
Kimi K2 Thinking58 outputs, specs and price
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