What is the difference between Gemini 3.5 Flash and GPT-5.1 Chat?

Gemini 3.5 Flash is developed by Google AI while GPT-5.1 Chat is developed by OpenAI. Gemini 3.5 Flash has a 1.0M token context window vs GPT-5.1 Chat's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.5 Flash or GPT-5.1 Chat?

It depends on your use case. Gemini 3.5 Flash and GPT-5.1 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 Gemini 3.5 Flash cost compared to GPT-5.1 Chat?

Gemini 3.5 Flash costs $1.5/M input tokens and GPT-5.1 Chat costs $1.25/M input tokens. GPT-5.1 Chat is $0.25/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 3.5 Flash and GPT-5.1 Chat on Rival?

This page shows a side-by-side comparison of Gemini 3.5 Flash and GPT-5.1 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 Gemini 3.5 Flash and GPT-5.1 Chat?

Gemini 3.5 Flash is developed by Google AI while GPT-5.1 Chat is developed by OpenAI. Gemini 3.5 Flash has a 1.0M token context window vs GPT-5.1 Chat's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.5 Flash or GPT-5.1 Chat?

It depends on your use case. Gemini 3.5 Flash and GPT-5.1 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 Gemini 3.5 Flash cost compared to GPT-5.1 Chat?

Gemini 3.5 Flash costs $1.5/M input tokens and GPT-5.1 Chat costs $1.25/M input tokens. GPT-5.1 Chat is $0.25/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 3.5 Flash and GPT-5.1 Chat on Rival?

This page shows a side-by-side comparison of Gemini 3.5 Flash and GPT-5.1 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.

Gemini 3.5 Flash vs GPT-5.1 Chat: Which Is Better?

Updated May 2026

Our Verdict

Gemini 3.5 Flash

GPT-5.1 ChatRunner-up

No community votes yet. On paper, Gemini 3.5 Flash has the edge — newer, bigger context window.

Too close to call

API pricing

Cost per 1M tokens

Gemini 3.5 Flash

Input

$1.50

Output

$9.00

1.1× cheaper

GPT-5.1 Chat

Input

$1.25

1.2× cheaper

Output

$10.00

GPT-5.1 Chat wins input (1.2× cheaper)·Gemini 3.5 Flash wins output (1.1× cheaper)

Writing DNA

Style Comparison

Similarity

55%

Gemini 3.5 Flash uses 89.0x more headings

Gemini 3.5 Flash

GPT-5.1 Chat

59%Vocabulary73%

18wSentence Length18w

0.16Hedging0.45

4.4Bold1.1

3.0Lists2.4

0.00Emoji0.00

0.89Headings0.00

0.11Transitions0.06

Based on 27 + 15 text responses

Research

What we learned reading every model

Gemini 3.5 Flash and GPT-5.1 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 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Meta: Muse Spark 1.1New provider

GPT-5.1 Chat vs Claude Sonnet 4New provider

Updated May 2026

Our Verdict

Gemini 3.5 Flash

GPT-5.1 ChatRunner-up

No community votes yet. On paper, Gemini 3.5 Flash has the edge — newer, bigger context window.

Too close to call

API pricing

Cost per 1M tokens

Gemini 3.5 Flash

Input

$1.50

Output

$9.00

1.1× cheaper

GPT-5.1 Chat

Input

$1.25

1.2× cheaper

Output

$10.00

GPT-5.1 Chat wins input (1.2× cheaper)·Gemini 3.5 Flash wins output (1.1× cheaper)

Writing DNA

Style Comparison

Similarity

55%

Gemini 3.5 Flash uses 89.0x more headings

Gemini 3.5 Flash

GPT-5.1 Chat

59%Vocabulary73%

18wSentence Length18w

0.16Hedging0.45

4.4Bold1.1

3.0Lists2.4

0.00Emoji0.00

0.89Headings0.00

0.11Transitions0.06

Based on 27 + 15 text responses

Research

What we learned reading every model

Gemini 3.5 Flash and GPT-5.1 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 Chat vs MiniMax M3New provider

GPT-5.1 Chat vs Meta: Muse Spark 1.1New provider

GPT-5.1 Chat vs Claude Sonnet 4New provider