What is the difference between ChatGPT-4o (March 2025) and Claude Opus 4.8?

ChatGPT-4o (March 2025) is developed by OpenAI while Claude Opus 4.8 is developed by Anthropic. ChatGPT-4o (March 2025) has a 128K token context window vs Claude Opus 4.8's 1.0M. You can compare their actual outputs across 32 challenges on Rival to see how they differ in practice.

Which is better, ChatGPT-4o (March 2025) or Claude Opus 4.8?

It depends on your use case. ChatGPT-4o (March 2025) and Claude Opus 4.8 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 32 challenges so you can judge which fits your needs best.

How much does ChatGPT-4o (March 2025) cost compared to Claude Opus 4.8?

ChatGPT-4o (March 2025) costs $5/M input tokens and Claude Opus 4.8 costs $5/M input tokens. Claude Opus 4.8 is $0.00/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 ChatGPT-4o (March 2025) and Claude Opus 4.8 on Rival?

This page shows a side-by-side comparison of ChatGPT-4o (March 2025) and Claude Opus 4.8 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 May 2026

ChatGPT-4o (March 2025)vsClaude Opus 4.8

Claude Opus 4.8 has a larger context window than ChatGPT-4o (March 2025) (1.0M tokens vs 128K tokens).

ChatGPT-4o (March 2025) and Claude Opus 4.8 compared across 32 shared prompts
Spec	ChatGPT-4o (March 2025)	Claude Opus 4.8
Input price	$5/M tokens	$5/M tokens
Output price	$15/M tokens	$25/M tokens
Context window	128K tokens	1.0M tokens
Weights	—	Closed
Free API (OpenRouter)	No	No
Released	Mar 2025	May 2026