What is the difference between Claude Sonnet 4 and GPT-5.1-Codex?

Claude Sonnet 4 is developed by Anthropic while GPT-5.1-Codex is developed by OpenAI. Claude Sonnet 4 has a 200K token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4 or GPT-5.1-Codex?

It depends on your use case. Claude Sonnet 4 and GPT-5.1-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4 cost compared to GPT-5.1-Codex?

Claude Sonnet 4 costs $3/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $1.75/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 Sonnet 4 and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4 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 Sonnet 4 and GPT-5.1-Codex?

Claude Sonnet 4 is developed by Anthropic while GPT-5.1-Codex is developed by OpenAI. Claude Sonnet 4 has a 200K token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4 or GPT-5.1-Codex?

It depends on your use case. Claude Sonnet 4 and GPT-5.1-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4 cost compared to GPT-5.1-Codex?

Claude Sonnet 4 costs $3/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $1.75/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 Sonnet 4 and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4 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 Sonnet 4 vs GPT-5.1-Codex: Which Is Better?

Updated Nov 2025

Our Verdict

GPT-5.1-Codex

Claude Sonnet 4Runner-up

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

Slight edge

API pricing

Cost per 1M tokens

Claude Sonnet 4

Input

$3.00

Output

$15.00

GPT-5.1-Codex

Input

$1.25

2.4× cheaper

Output

$10.00

1.5× cheaper

GPT-5.1-Codex is cheaper on both — 2.4× input, 1.5× output

Writing DNA

Style Comparison

Similarity

48%

Claude Sonnet 4 uses 87.9x more emoji

Claude Sonnet 4

GPT-5.1-Codex

62%Vocabulary70%

111wSentence Length17w

0.40Hedging0.39

5.0Bold3.4

9.3Lists3.5

0.88Emoji0.00

2.16Headings0.50

0.33Transitions0.38

Based on 17 + 14 text responses

Research

What we learned reading every model

Claude Sonnet 4 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

GPT-5.1-Codex vs MiniMax M3New provider

GPT-5.1-Codex vs Claude Opus 4Cross-provider

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

Updated Nov 2025

Our Verdict

GPT-5.1-Codex

Claude Sonnet 4Runner-up

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

Slight edge

API pricing

Cost per 1M tokens

Claude Sonnet 4

Input

$3.00

Output

$15.00

GPT-5.1-Codex

Input

$1.25

2.4× cheaper

Output

$10.00

1.5× cheaper

GPT-5.1-Codex is cheaper on both — 2.4× input, 1.5× output

Writing DNA

Style Comparison

Similarity

48%

Claude Sonnet 4 uses 87.9x more emoji

Claude Sonnet 4

GPT-5.1-Codex

62%Vocabulary70%

111wSentence Length17w

0.40Hedging0.39

5.0Bold3.4

9.3Lists3.5

0.88Emoji0.00

2.16Headings0.50

0.33Transitions0.38

Based on 17 + 14 text responses

Research

What we learned reading every model

Claude Sonnet 4 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

GPT-5.1-Codex vs MiniMax M3New provider

GPT-5.1-Codex vs Claude Opus 4Cross-provider

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