What is the difference between GPT-4o (Omni) and Kimi K2.5?

GPT-4o (Omni) is developed by OpenAI while Kimi K2.5 is developed by Moonshot AI. GPT-4o (Omni) has a 128K token context window vs Kimi K2.5's 262K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, GPT-4o (Omni) or Kimi K2.5?

It depends on your use case. GPT-4o (Omni) and Kimi K2.5 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does GPT-4o (Omni) cost compared to Kimi K2.5?

GPT-4o (Omni) costs $2.5/M input tokens and Kimi K2.5 costs $0.6/M input tokens. Kimi K2.5 is $1.90/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-4o (Omni) and Kimi K2.5 on Rival?

This page shows a side-by-side comparison of GPT-4o (Omni) and Kimi K2.5 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 Jan 2026

GPT-4o (Omni)vsKimi K2.5

Kimi K2.5 is cheaper than GPT-4o (Omni) at $0.6/M vs $2.5/M input tokens.

GPT-4o (Omni) and Kimi K2.5 compared across 53 shared prompts
Spec	GPT-4o (Omni)	Kimi K2.5
Input price	$2.5/M tokens	$0.6/M tokens
Output price	$10/M tokens	$3/M tokens
Context window	128K tokens	262K tokens
Weights	Closed	Open
Free API (OpenRouter)	No	No
Released	May 2024	Jan 2026