What is the difference between Gemini 3.1 Pro Preview and GPT-5.1-Codex?

Gemini 3.1 Pro Preview is developed by Google AI while GPT-5.1-Codex is developed by OpenAI. Gemini 3.1 Pro Preview has a 1.0M token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.1 Pro Preview or GPT-5.1-Codex?

It depends on your use case. Gemini 3.1 Pro Preview and GPT-5.1-Codex 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 Gemini 3.1 Pro Preview cost compared to GPT-5.1-Codex?

Gemini 3.1 Pro Preview costs $2/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $0.75/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 Gemini 3.1 Pro Preview and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of Gemini 3.1 Pro Preview 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 Gemini 3.1 Pro Preview and GPT-5.1-Codex?

Gemini 3.1 Pro Preview is developed by Google AI while GPT-5.1-Codex is developed by OpenAI. Gemini 3.1 Pro Preview has a 1.0M token context window vs GPT-5.1-Codex's 400K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.1 Pro Preview or GPT-5.1-Codex?

It depends on your use case. Gemini 3.1 Pro Preview and GPT-5.1-Codex 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 Gemini 3.1 Pro Preview cost compared to GPT-5.1-Codex?

Gemini 3.1 Pro Preview costs $2/M input tokens and GPT-5.1-Codex costs $1.25/M input tokens. GPT-5.1-Codex is $0.75/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 Gemini 3.1 Pro Preview and GPT-5.1-Codex on Rival?

This page shows a side-by-side comparison of Gemini 3.1 Pro Preview 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.

Gemini 3.1 Pro Preview vs GPT-5.1-Codex: Which Is Better?

Updated Feb 2026

Our Verdict

Gemini 3.1 Pro Preview

GPT-5.1-CodexRunner-up

No community votes yet. On paper, Gemini 3.1 Pro Preview has the edge — newer, bigger context window.

Too close to call

API pricing

Cost per 1M tokens

Gemini 3.1 Pro Preview

Input

$2.00

Output

$12.00

GPT-5.1-Codex

Input

$1.25

1.6× cheaper

Output

$10.00

1.2× cheaper

GPT-5.1-Codex is cheaper on both — 1.6× input, 1.2× output

Writing DNA

Style Comparison

Similarity

45%

GPT-5.1-Codex uses 2.7x more transitions

Gemini 3.1 Pro Preview

GPT-5.1-Codex

54%Vocabulary70%

18wSentence Length17w

0.29Hedging0.39

4.9Bold3.4

3.3Lists3.5

0.00Emoji0.00

0.72Headings0.50

0.14Transitions0.38

Based on 23 + 14 text responses

Research

What we learned reading every model

Gemini 3.1 Pro Preview 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 Thinking Machines: InklingNew provider

GPT-5.1-Codex vs Gemini 3.6 FlashCross-provider

Updated Feb 2026

Our Verdict

Gemini 3.1 Pro Preview

GPT-5.1-CodexRunner-up

No community votes yet. On paper, Gemini 3.1 Pro Preview has the edge — newer, bigger context window.

Too close to call

API pricing

Cost per 1M tokens

Gemini 3.1 Pro Preview

Input

$2.00

Output

$12.00

GPT-5.1-Codex

Input

$1.25

1.6× cheaper

Output

$10.00

1.2× cheaper

GPT-5.1-Codex is cheaper on both — 1.6× input, 1.2× output

Writing DNA

Style Comparison

Similarity

45%

GPT-5.1-Codex uses 2.7x more transitions

Gemini 3.1 Pro Preview

GPT-5.1-Codex

54%Vocabulary70%

18wSentence Length17w

0.29Hedging0.39

4.9Bold3.4

3.3Lists3.5

0.00Emoji0.00

0.72Headings0.50

0.14Transitions0.38

Based on 23 + 14 text responses

Research

What we learned reading every model

Gemini 3.1 Pro Preview 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 Thinking Machines: InklingNew provider

GPT-5.1-Codex vs Gemini 3.6 FlashCross-provider