What is the difference between Claude Opus 5.5 and GPT-6 Astra Pro?

Claude Opus 5.5 is developed by Anthropic while GPT-6 Astra Pro is developed by OpenAI. Claude Opus 5.5 has a 1.0M 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, Claude Opus 5.5 or GPT-6 Astra Pro?

It depends on your use case. Claude Opus 5.5 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 Claude Opus 5.5 cost compared to GPT-6 Astra Pro?

Claude Opus 5.5 costs $4/M input tokens and GPT-6 Astra Pro costs $10/M input tokens. Claude Opus 5.5 is $6.00/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 Claude Opus 5.5 and GPT-6 Astra Pro on Rival?

This page shows a side-by-side comparison of Claude Opus 5.5 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

Claude Opus 5.5vsGPT-6 Astra Pro

Claude Opus 5.5 is cheaper than GPT-6 Astra Pro at $4/M vs $10/M input tokens.

Claude Opus 5.5 and GPT-6 Astra Pro compared across 2 shared prompts
Spec	Claude Opus 5.5	GPT-6 Astra Pro
Input price	$4/M tokens	$10/M tokens
Output price	$20/M tokens	$50/M tokens
Context window	1.0M tokens	1.1M tokens
Weights	Closed	Closed
Free API (OpenRouter)	No	No
Released	Sep 2026	Sep 2026

Our Verdict

GPT-6 Astra Pro

Claude Opus 5.5Runner-up

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

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Opus 5.5

Input

$4.00

2.5× cheaper

Output

$20.00

2.5× cheaper

GPT-6 Astra Pro

Input

$10.00

Output

$50.00

Claude Opus 5.5 is cheaper on both: 2.5× input, 2.5× output.

Where to run it

6 hosts

Claude Opus 5.54 hosts

HostInOutContextUptime

Amazon Bedrock$4.00 in$20.00 out1M99.8% up Azure AI Foundry$4.00 in$20.00 out1M100% up Anthropic$4.00 in$20.00 out1M100% up Google Vertex AI$4.00 in$20.00 out1M100% up

GPT-6 Astra Pro2 hosts

HostInOutContextUptime

Azure AI Foundry$10.00 in$50.00 out1.1M100% up OpenAI$10.00 in$50.00 out1.1M99.4% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Cost per 1M tokens

6 hosts

What we learned reading every model

Common questions

What is the difference between Claude Opus 5.5 and GPT-6 Astra Pro?

Which is better, Claude Opus 5.5 or GPT-6 Astra Pro?

How much does Claude Opus 5.5 cost compared to GPT-6 Astra Pro?

How can I compare Claude Opus 5.5 and GPT-6 Astra Pro on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages

Cost per 1M tokens

6 hosts

What we learned reading every model

Common questions

What is the difference between Claude Opus 5.5 and GPT-6 Astra Pro?

Which is better, Claude Opus 5.5 or GPT-6 Astra Pro?

How much does Claude Opus 5.5 cost compared to GPT-6 Astra Pro?

How can I compare Claude Opus 5.5 and GPT-6 Astra Pro on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages