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

Both are developed by OpenAI but target different use cases. GPT-5.1 has a 400K token context window vs GPT-5.1-Codex's 400K. in 11 community votes on Rival, GPT-5.1 wins 56% of head-to-head matchups. These results are based on blind head-to-head voting across 52 challenges.

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

Based on 11 community votes on Rival, GPT-5.1 wins 56% of head-to-head matchups against GPT-5.1-Codex. GPT-5.1 is strongest in Web Design. However, GPT-5.1-Codex leads in Reasoning.

How much does GPT-5.1 cost compared to GPT-5.1-Codex?

GPT-5.1 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. The more expensive model wins 56% of duels, so the premium may be justified by quality.

How are GPT-5.1 vs GPT-5.1-Codex votes collected on Rival?

Rival presents both models' outputs side-by-side in blind duels. Voters see the responses but don't know which model produced each one, eliminating brand bias. 11 votes have been collected for this pair across 52 challenges. All vote data is part of Rival's open dataset.

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

Both are developed by OpenAI but target different use cases. GPT-5.1 has a 400K token context window vs GPT-5.1-Codex's 400K. in 11 community votes on Rival, GPT-5.1 wins 56% of head-to-head matchups. These results are based on blind head-to-head voting across 52 challenges.

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

Based on 11 community votes on Rival, GPT-5.1 wins 56% of head-to-head matchups against GPT-5.1-Codex. GPT-5.1 is strongest in Web Design. However, GPT-5.1-Codex leads in Reasoning.

How much does GPT-5.1 cost compared to GPT-5.1-Codex?

GPT-5.1 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. The more expensive model wins 56% of duels, so the premium may be justified by quality.

How are GPT-5.1 vs GPT-5.1-Codex votes collected on Rival?

Rival presents both models' outputs side-by-side in blind duels. Voters see the responses but don't know which model produced each one, eliminating brand bias. 11 votes have been collected for this pair across 52 challenges. All vote data is part of Rival's open dataset.

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

Updated Nov 2025

Our Verdict

GPT-5.1Winner

GPT-5.1-CodexRunner-up

GPT-5.1 has the edge overall. In 11 blind votes, GPT-5.1 wins 56% of the time.

Pick GPT-5.1 for Web Design. Pick GPT-5.1-Codex for Reasoning.

Slight edge

API pricing

Cost per 1M tokens

GPT-5.1

Input

$1.25

Output

$10.00

GPT-5.1-Codex

Input

$1.25

Output

$10.00

Writing DNA

Style Comparison

Similarity

55%

GPT-5.1-Codex uses 14.0x more transitions

GPT-5.1

GPT-5.1-Codex

62%Vocabulary70%

19wSentence Length17w

0.29Hedging0.39

3.5Bold3.4

7.2Lists3.5

0.00Emoji0.00

0.61Headings0.50

0.03Transitions0.38

Based on 14 + 14 text responses

Research

What we learned reading every model

GPT-5.1 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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GPT-5.1 vs MiniMax M3New provider

GPT-5.1 vs Grok 3New provider

GPT-5.1 vs Llama 4 MaverickNew provider

Updated Nov 2025

Our Verdict

GPT-5.1Winner

GPT-5.1-CodexRunner-up

GPT-5.1 has the edge overall. In 11 blind votes, GPT-5.1 wins 56% of the time.

Pick GPT-5.1 for Web Design. Pick GPT-5.1-Codex for Reasoning.

Slight edge

API pricing

Cost per 1M tokens

GPT-5.1

Input

$1.25

Output

$10.00

GPT-5.1-Codex

Input

$1.25

Output

$10.00

Writing DNA

Style Comparison

Similarity

55%

GPT-5.1-Codex uses 14.0x more transitions

GPT-5.1

GPT-5.1-Codex

62%Vocabulary70%

19wSentence Length17w

0.29Hedging0.39

3.5Bold3.4

7.2Lists3.5

0.00Emoji0.00

0.61Headings0.50

0.03Transitions0.38

Based on 14 + 14 text responses

Research

What we learned reading every model

GPT-5.1 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 vs MiniMax M3New provider

GPT-5.1 vs Grok 3New provider

GPT-5.1 vs Llama 4 MaverickNew provider