What is the difference between Claude 3 Opus and GPT-5 Codex?

Claude 3 Opus is developed by Anthropic while GPT-5 Codex is developed by OpenAI. You can compare their actual outputs across 11 challenges on Rival to see how they differ in practice.

Which is better, Claude 3 Opus or GPT-5 Codex?

It depends on your use case. Claude 3 Opus and GPT-5 Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 11 challenges so you can judge which fits your needs best.

How can I compare Claude 3 Opus and GPT-5 Codex on Rival?

This page shows a side-by-side comparison of Claude 3 Opus and GPT-5 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 Codex?

Claude 3 Opus is developed by Anthropic while GPT-5 Codex is developed by OpenAI. You can compare their actual outputs across 11 challenges on Rival to see how they differ in practice.

Which is better, Claude 3 Opus or GPT-5 Codex?

It depends on your use case. Claude 3 Opus and GPT-5 Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 11 challenges so you can judge which fits your needs best.

How can I compare Claude 3 Opus and GPT-5 Codex on Rival?

This page shows a side-by-side comparison of Claude 3 Opus and GPT-5 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 Codex: Which Is Better?

Updated Sep 2025

Our Verdict

Claude 3 Opus

GPT-5 Codex

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call

API pricing

Cost per 1M tokens

Claude 3 Opus

Input

$15.00

Output

$75.00

GPT-5 Codex

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

58%

GPT-5 Codex uses 229.7x more bold

Claude 3 Opus

GPT-5 Codex

54%Vocabulary64%

14wSentence Length17w

0.48Hedging0.38

0.0Bold2.3

3.0Lists3.5

0.00Emoji0.15

0.00Headings0.49

0.06Transitions0.05

Based on 3 + 13 text responses

Research

What we learned reading every model

Claude 3 Opus and GPT-5 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

Updated Sep 2025

Our Verdict

Claude 3 Opus

GPT-5 Codex

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call

API pricing

Cost per 1M tokens

Claude 3 Opus

Input

$15.00

Output

$75.00

GPT-5 Codex

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

58%

GPT-5 Codex uses 229.7x more bold

Claude 3 Opus

GPT-5 Codex

54%Vocabulary64%

14wSentence Length17w

0.48Hedging0.38

0.0Bold2.3

3.0Lists3.5

0.00Emoji0.15

0.00Headings0.49

0.06Transitions0.05

Based on 3 + 13 text responses

Research

What we learned reading every model

Claude 3 Opus and GPT-5 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