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

GPT-5.1 Chat is developed by OpenAI while Kimi K2 Thinking is developed by Moonshot AI. GPT-5.1 Chat has a 128K token context window vs Kimi K2 Thinking's 262K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1 Chat or Kimi K2 Thinking?

It depends on your use case. GPT-5.1 Chat and Kimi K2 Thinking 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 Chat cost compared to Kimi K2 Thinking?

GPT-5.1 Chat costs $1.25/M input tokens and Kimi K2 Thinking costs $0.6/M input tokens. Kimi K2 Thinking is $0.65/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 Chat and Kimi K2 Thinking on Rival?

This page shows a side-by-side comparison of GPT-5.1 Chat and Kimi K2 Thinking 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.

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

GPT-5.1 Chat is developed by OpenAI while Kimi K2 Thinking is developed by Moonshot AI. GPT-5.1 Chat has a 128K token context window vs Kimi K2 Thinking's 262K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1 Chat or Kimi K2 Thinking?

It depends on your use case. GPT-5.1 Chat and Kimi K2 Thinking 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 Chat cost compared to Kimi K2 Thinking?

GPT-5.1 Chat costs $1.25/M input tokens and Kimi K2 Thinking costs $0.6/M input tokens. Kimi K2 Thinking is $0.65/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 Chat and Kimi K2 Thinking on Rival?

This page shows a side-by-side comparison of GPT-5.1 Chat and Kimi K2 Thinking 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.

GPT-5.1 Chat vs Kimi K2 Thinking: Which Is Better?

Updated Nov 2025

Our Verdict

Kimi K2 Thinking

GPT-5.1 ChatRunner-up

No community votes yet. On paper, Kimi K2 Thinking has the edge — bigger model tier, bigger context window.

Kimi K2 Thinking is 4.0x cheaper per token — worth considering if cost matters.

Too close to call

What do GPT-5.1 Chat and Kimi K2 Thinking say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

GPT-5.1 Chat

Input

$1.25

Output

$10.00

Kimi K2 Thinking

Input

$0.60

2.1× cheaper

Output

$2.50

4.0× cheaper

Kimi K2 Thinking is cheaper on both — 2.1× input, 4.0× output

Writing DNA

Style Comparison

Similarity

38%

Kimi K2 Thinking uses 56.4x more headings

GPT-5.1 Chat

Kimi K2 Thinking

73%Vocabulary57%

18wSentence Length26w

0.45Hedging0.36

1.1Bold5.8

2.4Lists6.0

0.00Emoji0.00

0.00Headings0.56

0.06Transitions0.06

Based on 15 + 14 text responses

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

GPT-5.1 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Ox AlphaNew provider

GPT-5.1 Chat vs Grok 3New provider

Updated Nov 2025

Our Verdict

Kimi K2 Thinking

GPT-5.1 ChatRunner-up

No community votes yet. On paper, Kimi K2 Thinking has the edge — bigger model tier, bigger context window.

Kimi K2 Thinking is 4.0x cheaper per token — worth considering if cost matters.

Too close to call

What do GPT-5.1 Chat and Kimi K2 Thinking say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

GPT-5.1 Chat

Input

$1.25

Output

$10.00

Kimi K2 Thinking

Input

$0.60

2.1× cheaper

Output

$2.50

4.0× cheaper

Kimi K2 Thinking is cheaper on both — 2.1× input, 4.0× output

Writing DNA

Style Comparison

Similarity

38%

Kimi K2 Thinking uses 56.4x more headings

GPT-5.1 Chat

Kimi K2 Thinking

73%Vocabulary57%

18wSentence Length26w

0.45Hedging0.36

1.1Bold5.8

2.4Lists6.0

0.00Emoji0.00

0.00Headings0.56

0.06Transitions0.06

Based on 15 + 14 text responses

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

GPT-5.1 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Ox AlphaNew provider

GPT-5.1 Chat vs Grok 3New provider