What is the difference between Claude Opus 5 and GPT-5.1 Chat?

Claude Opus 5 is developed by Anthropic while GPT-5.1 Chat is developed by OpenAI. Claude Opus 5 has a 1.0M token context window vs GPT-5.1 Chat's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 5 or GPT-5.1 Chat?

It depends on your use case. Claude Opus 5 and GPT-5.1 Chat 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 Claude Opus 5 cost compared to GPT-5.1 Chat?

Claude Opus 5 costs $5/M input tokens and GPT-5.1 Chat costs $1.25/M input tokens. GPT-5.1 Chat is $3.75/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 and GPT-5.1 Chat on Rival?

This page shows a side-by-side comparison of Claude Opus 5 and GPT-5.1 Chat 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.

What is the difference between Claude Opus 5 and GPT-5.1 Chat?

Claude Opus 5 is developed by Anthropic while GPT-5.1 Chat is developed by OpenAI. Claude Opus 5 has a 1.0M token context window vs GPT-5.1 Chat's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 5 or GPT-5.1 Chat?

It depends on your use case. Claude Opus 5 and GPT-5.1 Chat 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 Claude Opus 5 cost compared to GPT-5.1 Chat?

Claude Opus 5 costs $5/M input tokens and GPT-5.1 Chat costs $1.25/M input tokens. GPT-5.1 Chat is $3.75/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 and GPT-5.1 Chat on Rival?

This page shows a side-by-side comparison of Claude Opus 5 and GPT-5.1 Chat 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.

Claude Opus 5 vs GPT-5.1 Chat: Which Is Better?

Updated Jul 2026

Our Verdict

Claude Opus 5

GPT-5.1 ChatRunner-up

No community votes yet. On paper, Claude Opus 5 has the edge — bigger model tier, newer, bigger context window.

Slight edge

API pricing

Cost per 1M tokens

Claude Opus 5

Input

$5.00

Output

$25.00

GPT-5.1 Chat

Input

$1.25

4.0× cheaper

Output

$10.00

2.5× cheaper

GPT-5.1 Chat is cheaper on both — 4.0× input, 2.5× output

Writing DNA

Style Comparison

Similarity

66%

Claude Opus 5 uses 1.7x more emoji

Claude Opus 5

GPT-5.1 Chat

54%Vocabulary73%

21wSentence Length18w

0.40Hedging0.45

3.9Bold1.1

1.9Lists2.4

0.02Emoji0.00

0.71Headings0.00

0.05Transitions0.06

Based on 27 + 15 text responses

Research

What we learned reading every model

Claude Opus 5 and GPT-5.1 Chat have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

GPT-5.1 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Gemini 2.5 Pro Preview 06-05New provider

GPT-5.1 Chat vs Claude Opus 4Cross-provider

Updated Jul 2026

Our Verdict

Claude Opus 5

GPT-5.1 ChatRunner-up

No community votes yet. On paper, Claude Opus 5 has the edge — bigger model tier, newer, bigger context window.

Slight edge

API pricing

Cost per 1M tokens

Claude Opus 5

Input

$5.00

Output

$25.00

GPT-5.1 Chat

Input

$1.25

4.0× cheaper

Output

$10.00

2.5× cheaper

GPT-5.1 Chat is cheaper on both — 4.0× input, 2.5× output

Writing DNA

Style Comparison

Similarity

66%

Claude Opus 5 uses 1.7x more emoji

Claude Opus 5

GPT-5.1 Chat

54%Vocabulary73%

21wSentence Length18w

0.40Hedging0.45

3.9Bold1.1

1.9Lists2.4

0.02Emoji0.00

0.71Headings0.00

0.05Transitions0.06

Based on 27 + 15 text responses

Research

What we learned reading every model

Claude Opus 5 and GPT-5.1 Chat have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

GPT-5.1 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Gemini 2.5 Pro Preview 06-05New provider

GPT-5.1 Chat vs Claude Opus 4Cross-provider