What is the difference between GPT-5.1-Codex and GPT-5.3 Chat?

Both are developed by OpenAI but target different use cases. GPT-5.1-Codex has a 400K token context window vs GPT-5.3 Chat's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1-Codex or GPT-5.3 Chat?

It depends on your use case. GPT-5.1-Codex and GPT-5.3 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 GPT-5.1-Codex cost compared to GPT-5.3 Chat?

GPT-5.1-Codex costs $1.25/M input tokens and GPT-5.3 Chat costs $1.75/M input tokens. GPT-5.1-Codex is $0.50/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-Codex and GPT-5.3 Chat on Rival?

This page shows a side-by-side comparison of GPT-5.1-Codex and GPT-5.3 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 GPT-5.1-Codex and GPT-5.3 Chat?

Both are developed by OpenAI but target different use cases. GPT-5.1-Codex has a 400K token context window vs GPT-5.3 Chat's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1-Codex or GPT-5.3 Chat?

It depends on your use case. GPT-5.1-Codex and GPT-5.3 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 GPT-5.1-Codex cost compared to GPT-5.3 Chat?

GPT-5.1-Codex costs $1.25/M input tokens and GPT-5.3 Chat costs $1.75/M input tokens. GPT-5.1-Codex is $0.50/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-Codex and GPT-5.3 Chat on Rival?

This page shows a side-by-side comparison of GPT-5.1-Codex and GPT-5.3 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.

GPT-5.1-Codex vs GPT-5.3 Chat: Which Is Better?

Updated Mar 2026

Our Verdict

GPT-5.1-Codex

GPT-5.3 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-Codex

Input

$1.25

1.4× cheaper

Output

$10.00

1.4× cheaper

GPT-5.3 Chat

Input

$1.75

Output

$14.00

GPT-5.1-Codex is cheaper on both — 1.4× input, 1.4× output

Writing DNA

Style Comparison

Similarity

61%

GPT-5.1-Codex uses 50.1x more headings

GPT-5.1-Codex

GPT-5.3 Chat

70%Vocabulary59%

17wSentence Length26w

0.39Hedging0.84

3.4Bold1.7

3.5Lists6.6

0.00Emoji0.00

0.50Headings0.00

0.38Transitions0.25

Based on 14 + 23 text responses

Research

What we learned reading every model

GPT-5.1-Codex and GPT-5.3 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-Codex vs MiniMax M3New provider

GPT-5.1-Codex vs Grok 3New provider

GPT-5.1-Codex vs Llama 4 MaverickNew provider

Updated Mar 2026

Our Verdict

GPT-5.1-Codex

GPT-5.3 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-Codex

Input

$1.25

1.4× cheaper

Output

$10.00

1.4× cheaper

GPT-5.3 Chat

Input

$1.75

Output

$14.00

GPT-5.1-Codex is cheaper on both — 1.4× input, 1.4× output

Writing DNA

Style Comparison

Similarity

61%

GPT-5.1-Codex uses 50.1x more headings

GPT-5.1-Codex

GPT-5.3 Chat

70%Vocabulary59%

17wSentence Length26w

0.39Hedging0.84

3.4Bold1.7

3.5Lists6.6

0.00Emoji0.00

0.50Headings0.00

0.38Transitions0.25

Based on 14 + 23 text responses

Research

What we learned reading every model

GPT-5.1-Codex and GPT-5.3 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-Codex vs MiniMax M3New provider

GPT-5.1-Codex vs Grok 3New provider

GPT-5.1-Codex vs Llama 4 MaverickNew provider