What is the difference between GPT-5.1 Chat and GPT-5.1-Codex?

Both are developed by OpenAI but target different use cases. GPT-5.1 Chat has a 128K 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, GPT-5.1 Chat or GPT-5.1-Codex?

It depends on your use case. GPT-5.1 Chat 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 GPT-5.1 Chat cost compared to GPT-5.1-Codex?

GPT-5.1 Chat costs $1.25/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $0.00/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 GPT-5.1 Chat and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of GPT-5.1 Chat 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 GPT-5.1 Chat and GPT-5.1-Codex?

Both are developed by OpenAI but target different use cases. GPT-5.1 Chat has a 128K 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, GPT-5.1 Chat or GPT-5.1-Codex?

It depends on your use case. GPT-5.1 Chat 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 GPT-5.1 Chat cost compared to GPT-5.1-Codex?

GPT-5.1 Chat costs $1.25/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $0.00/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 GPT-5.1 Chat and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of GPT-5.1 Chat 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.

GPT-5.1 Chat vs GPT-5.1-Codex: Which Is Better?

Updated Nov 2025

Our Verdict

GPT-5.1-Codex

GPT-5.1 ChatRunner-up

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

Too close to call

API pricing

Cost per 1M tokens

GPT-5.1 Chat

Input

$1.25

Output

$10.00

GPT-5.1-Codex

Input

$1.25

Output

$10.00

Writing DNA

Style Comparison

Similarity

72%

GPT-5.1-Codex uses 50.1x more headings

GPT-5.1 Chat

GPT-5.1-Codex

73%Vocabulary70%

18wSentence Length17w

0.45Hedging0.39

1.1Bold3.4

2.4Lists3.5

0.00Emoji0.00

0.00Headings0.50

0.06Transitions0.38

Based on 15 + 14 text responses

Research

What we learned reading every model

GPT-5.1 Chat 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 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Grok 3New provider

GPT-5.1 Chat vs Llama 4 MaverickNew provider

Updated Nov 2025

Our Verdict

GPT-5.1-Codex

GPT-5.1 ChatRunner-up

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

Too close to call

API pricing

Cost per 1M tokens

GPT-5.1 Chat

Input

$1.25

Output

$10.00

GPT-5.1-Codex

Input

$1.25

Output

$10.00

Writing DNA

Style Comparison

Similarity

72%

GPT-5.1-Codex uses 50.1x more headings

GPT-5.1 Chat

GPT-5.1-Codex

73%Vocabulary70%

18wSentence Length17w

0.45Hedging0.39

1.1Bold3.4

2.4Lists3.5

0.00Emoji0.00

0.00Headings0.50

0.06Transitions0.38

Based on 15 + 14 text responses

Research

What we learned reading every model

GPT-5.1 Chat 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 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Grok 3New provider

GPT-5.1 Chat vs Llama 4 MaverickNew provider