What is the difference between GPT-5.1 and Kimi K2 0905?

GPT-5.1 is developed by OpenAI while Kimi K2 0905 is developed by Moonshot AI. GPT-5.1 has a 400K token context window vs Kimi K2 0905'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 or Kimi K2 0905?

It depends on your use case. GPT-5.1 and Kimi K2 0905 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 cost compared to Kimi K2 0905?

GPT-5.1 costs $1.25/M input tokens and Kimi K2 0905 costs $0.6/M input tokens. Kimi K2 0905 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 and Kimi K2 0905 on Rival?

This page shows a side-by-side comparison of GPT-5.1 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.

Updated Nov 2025

GPT-5.1vsKimi K2 0905

Kimi K2 0905 is cheaper than GPT-5.1 at $0.6/M vs $1.25/M input tokens.

GPT-5.1 and Kimi K2 0905 compared across 52 shared prompts
Spec	GPT-5.1	Kimi K2 0905
Input price	$1.25/M tokens	$0.6/M tokens
Output price	$10/M tokens	$2.5/M tokens
Context window	400K tokens	262K tokens
Weights	Closed	Open
Free API (OpenRouter)	No	No
Released	Nov 2025	Sep 2025