What is the difference between ChatGPT-4o (March 2025) and GPT-6 Astra Pro?

Both are developed by OpenAI but target different use cases. ChatGPT-4o (March 2025) has a 128K token context window vs GPT-6 Astra Pro's 1.1M. You can compare their actual outputs across 2 challenges on Rival to see how they differ in practice.

Which is better, ChatGPT-4o (March 2025) or GPT-6 Astra Pro?

It depends on your use case. ChatGPT-4o (March 2025) and GPT-6 Astra Pro each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 2 challenges so you can judge which fits your needs best.

How much does ChatGPT-4o (March 2025) cost compared to GPT-6 Astra Pro?

ChatGPT-4o (March 2025) costs $5/M input tokens and GPT-6 Astra Pro costs $10/M input tokens. ChatGPT-4o (March 2025) is $5.00/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 GPT-6 Astra Pro on Rival?

This page shows a side-by-side comparison of ChatGPT-4o (March 2025) and GPT-6 Astra Pro 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 Sep 2026

ChatGPT-4o (March 2025)vsGPT-6 Astra Pro

ChatGPT-4o (March 2025) is cheaper than GPT-6 Astra Pro at $5/M vs $10/M input tokens.

ChatGPT-4o (March 2025) and GPT-6 Astra Pro compared across 2 shared prompts
Spec	ChatGPT-4o (March 2025)	GPT-6 Astra Pro
Input price	$5/M tokens	$10/M tokens
Output price	$15/M tokens	$50/M tokens
Context window	128K tokens	1.1M tokens
Weights	—	Closed
Free API (OpenRouter)	No	No
Released	Mar 2025	Sep 2026

Our Verdict

GPT-6 Astra Pro

ChatGPT-4o (March 2025)Runner-up

Not enough votes to call it. On the specs, GPT-6 Astra Pro has the edge: newer, bigger context window.

ChatGPT-4o (March 2025) costs 3.3x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

ChatGPT-4o (March 2025)

Input

$5.00

2.0× cheaper

Output

$15.00

3.3× cheaper

GPT-6 Astra Pro

Input

$10.00

Output

$50.00

ChatGPT-4o (March 2025) is cheaper on both: 2.0× input, 3.3× output.

Where to run it

2 hosts

ChatGPT-4o (March 2025)

No hosts listed on OpenRouter.

GPT-6 Astra Pro2 hosts

HostInOutContextUptime

Azure AI Foundry$10.00 in$50.00 out1.1M98.9% up OpenAI$10.00 in$50.00 out1.1M99.6% up

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

Research

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Cost per 1M tokens

2 hosts

What we learned reading every model

Common questions

What is the difference between ChatGPT-4o (March 2025) and GPT-6 Astra Pro?

Which is better, ChatGPT-4o (March 2025) or GPT-6 Astra Pro?

How much does ChatGPT-4o (March 2025) cost compared to GPT-6 Astra Pro?

How can I compare ChatGPT-4o (March 2025) and GPT-6 Astra Pro on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

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Cost per 1M tokens

2 hosts

What we learned reading every model

Common questions

What is the difference between ChatGPT-4o (March 2025) and GPT-6 Astra Pro?

Which is better, ChatGPT-4o (March 2025) or GPT-6 Astra Pro?

How much does ChatGPT-4o (March 2025) cost compared to GPT-6 Astra Pro?

How can I compare ChatGPT-4o (March 2025) and GPT-6 Astra Pro on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages