What is the difference between Claude 3 Opus and GPT-5.1-Codex?

Claude 3 Opus is developed by Anthropic while GPT-5.1-Codex is developed by OpenAI. Claude 3 Opus has a 200K token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 12 challenges on Rival to see how they differ in practice.

Which is better, Claude 3 Opus or GPT-5.1-Codex?

It depends on your use case. Claude 3 Opus and GPT-5.1-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 12 challenges so you can judge which fits your needs best.

How much does Claude 3 Opus cost compared to GPT-5.1-Codex?

Claude 3 Opus costs $15/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $13.75/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 3 Opus and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of Claude 3 Opus and GPT-5.1-Codex 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 3 Opus and GPT-5.1-Codex?

Claude 3 Opus is developed by Anthropic while GPT-5.1-Codex is developed by OpenAI. Claude 3 Opus has a 200K token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 12 challenges on Rival to see how they differ in practice.

Which is better, Claude 3 Opus or GPT-5.1-Codex?

It depends on your use case. Claude 3 Opus and GPT-5.1-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 12 challenges so you can judge which fits your needs best.

How much does Claude 3 Opus cost compared to GPT-5.1-Codex?

Claude 3 Opus costs $15/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $13.75/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 3 Opus and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of Claude 3 Opus and GPT-5.1-Codex 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 3 Opus vs GPT-5.1-Codex: Which Is Better?

Updated Nov 2025

Our Verdict

GPT-5.1-Codex

Claude 3 OpusRunner-up

No community votes yet. On paper, GPT-5.1-Codex has the edge — newer, bigger context window.

GPT-5.1-Codex is 7.5x cheaper per token — worth considering if cost matters.

Too close to call

API pricing

Cost per 1M tokens

Claude 3 Opus

Input

$15.00

Output

$75.00

GPT-5.1-Codex

Input

$1.25

12× cheaper

Output

$10.00

7.5× cheaper

GPT-5.1-Codex is cheaper on both — 12× input, 7.5× output

Writing DNA

Style Comparison

Similarity

43%

GPT-5.1-Codex uses 343.9x more bold

Claude 3 Opus

GPT-5.1-Codex

54%Vocabulary70%

14wSentence Length17w

0.48Hedging0.39

0.0Bold3.4

3.0Lists3.5

0.00Emoji0.00

0.00Headings0.50

0.06Transitions0.38

Based on 3 + 14 text responses

Research

What we learned reading every model

Claude 3 Opus and GPT-5.1-Codex 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

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Claude 3 Opus vs Grok 3New provider

Updated Nov 2025

Our Verdict

GPT-5.1-Codex

Claude 3 OpusRunner-up

No community votes yet. On paper, GPT-5.1-Codex has the edge — newer, bigger context window.

GPT-5.1-Codex is 7.5x cheaper per token — worth considering if cost matters.

Too close to call

API pricing

Cost per 1M tokens

Claude 3 Opus

Input

$15.00

Output

$75.00

GPT-5.1-Codex

Input

$1.25

12× cheaper

Output

$10.00

7.5× cheaper

GPT-5.1-Codex is cheaper on both — 12× input, 7.5× output

Writing DNA

Style Comparison

Similarity

43%

GPT-5.1-Codex uses 343.9x more bold

Claude 3 Opus

GPT-5.1-Codex

54%Vocabulary70%

14wSentence Length17w

0.48Hedging0.39

0.0Bold3.4

3.0Lists3.5

0.00Emoji0.00

0.00Headings0.50

0.06Transitions0.38

Based on 3 + 14 text responses

Research

What we learned reading every model

Claude 3 Opus and GPT-5.1-Codex 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

Claude 3 Opus vs Llama 4 MaverickNew provider

Claude 3 Opus vs MiniMax M3New provider

Claude 3 Opus vs Grok 3New provider