What is the difference between Claude Sonnet 4.5 and GPT-4o (Omni)?

Claude Sonnet 4.5 is developed by Anthropic while GPT-4o (Omni) is developed by OpenAI. Claude Sonnet 4.5 has a 200K token context window vs GPT-4o (Omni)'s 128K. You can compare their actual outputs across 43 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or GPT-4o (Omni)?

It depends on your use case. Claude Sonnet 4.5 and GPT-4o (Omni) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 43 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4.5 cost compared to GPT-4o (Omni)?

Claude Sonnet 4.5 costs $3/M input tokens and GPT-4o (Omni) costs $2.5/M input tokens. GPT-4o (Omni) 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 Claude Sonnet 4.5 and GPT-4o (Omni) on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and GPT-4o (Omni) 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 Claude Sonnet 4.5 and GPT-4o (Omni)?

Claude Sonnet 4.5 is developed by Anthropic while GPT-4o (Omni) is developed by OpenAI. Claude Sonnet 4.5 has a 200K token context window vs GPT-4o (Omni)'s 128K. You can compare their actual outputs across 43 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or GPT-4o (Omni)?

It depends on your use case. Claude Sonnet 4.5 and GPT-4o (Omni) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 43 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4.5 cost compared to GPT-4o (Omni)?

Claude Sonnet 4.5 costs $3/M input tokens and GPT-4o (Omni) costs $2.5/M input tokens. GPT-4o (Omni) 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 Claude Sonnet 4.5 and GPT-4o (Omni) on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and GPT-4o (Omni) 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.

Claude Sonnet 4.5 vs GPT-4o (Omni): Which Is Better?

Updated Sep 2025

Our Verdict

Claude Sonnet 4.5

GPT-4o (Omni)

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call

API pricing

Cost per 1M tokens

Claude Sonnet 4.5

Input

$3.00

Output

$15.00

GPT-4o (Omni)

Input

$2.50

1.2× cheaper

Output

$10.00

1.5× cheaper

GPT-4o (Omni) is cheaper on both — 1.2× input, 1.5× output

Writing DNA

Style Comparison

Similarity

50%

Claude Sonnet 4.5 uses 18.0x more emoji

Claude Sonnet 4.5

GPT-4o (Omni)

64%Vocabulary54%

94wSentence Length18w

0.48Hedging0.72

4.9Bold7.3

8.0Lists5.6

0.45Emoji0.03

1.91Headings1.40

0.07Transitions0.26

Based on 20 + 24 text responses

Research

What we learned reading every model

Claude Sonnet 4.5 and GPT-4o (Omni) 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-4o (Omni) vs MiniMax M3New provider

Claude Sonnet 4.5 vs GPT-5Cross-provider

Claude Sonnet 4.5 vs Llama 4 MaverickNew provider

Updated Sep 2025

Our Verdict

Claude Sonnet 4.5

GPT-4o (Omni)

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call

API pricing

Cost per 1M tokens

Claude Sonnet 4.5

Input

$3.00

Output

$15.00

GPT-4o (Omni)

Input

$2.50

1.2× cheaper

Output

$10.00

1.5× cheaper

GPT-4o (Omni) is cheaper on both — 1.2× input, 1.5× output

Writing DNA

Style Comparison

Similarity

50%

Claude Sonnet 4.5 uses 18.0x more emoji

Claude Sonnet 4.5

GPT-4o (Omni)

64%Vocabulary54%

94wSentence Length18w

0.48Hedging0.72

4.9Bold7.3

8.0Lists5.6

0.45Emoji0.03

1.91Headings1.40

0.07Transitions0.26

Based on 20 + 24 text responses

Research

What we learned reading every model

Claude Sonnet 4.5 and GPT-4o (Omni) 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-4o (Omni) vs MiniMax M3New provider

Claude Sonnet 4.5 vs GPT-5Cross-provider

Claude Sonnet 4.5 vs Llama 4 MaverickNew provider