What is the difference between GPT-4.5 and GPT-5.3-Codex?

Both are developed by OpenAI but target different use cases. GPT-4.5 has a 128K token context window vs GPT-5.3-Codex's 400K. You can compare their actual outputs across 24 challenges on Rival to see how they differ in practice.

Which is better, GPT-4.5 or GPT-5.3-Codex?

It depends on your use case. GPT-4.5 and GPT-5.3-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 24 challenges so you can judge which fits your needs best.

How much does GPT-4.5 cost compared to GPT-5.3-Codex?

GPT-4.5 costs $75/M input tokens and GPT-5.3-Codex costs $1.75/M input tokens. GPT-5.3-Codex is $73.25/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 GPT-4.5 and GPT-5.3-Codex on Rival?

This page shows a side-by-side comparison of GPT-4.5 and GPT-5.3-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 GPT-4.5 and GPT-5.3-Codex?

Both are developed by OpenAI but target different use cases. GPT-4.5 has a 128K token context window vs GPT-5.3-Codex's 400K. You can compare their actual outputs across 24 challenges on Rival to see how they differ in practice.

Which is better, GPT-4.5 or GPT-5.3-Codex?

It depends on your use case. GPT-4.5 and GPT-5.3-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 24 challenges so you can judge which fits your needs best.

How much does GPT-4.5 cost compared to GPT-5.3-Codex?

GPT-4.5 costs $75/M input tokens and GPT-5.3-Codex costs $1.75/M input tokens. GPT-5.3-Codex is $73.25/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 GPT-4.5 and GPT-5.3-Codex on Rival?

This page shows a side-by-side comparison of GPT-4.5 and GPT-5.3-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.

GPT-4.5 vs GPT-5.3-Codex: Which Is Better?

Updated Feb 2026

Our Verdict

GPT-5.3-Codex

GPT-4.5Runner-up

No community votes yet. On paper, GPT-5.3-Codex has the edge — newer, bigger context window.

GPT-5.3-Codex is 11x cheaper per token — worth considering if cost matters.

Too close to call

API pricing

Cost per 1M tokens

GPT-4.5

Input

$75.00

Output

$150.00

GPT-5.3-Codex

Input

$1.75

43× cheaper

Output

$14.00

11× cheaper

GPT-5.3-Codex is cheaper on both — 43× input, 11× output

Writing DNA

Style Comparison

Similarity

61%

GPT-5.3-Codex uses 15.8x more emoji

GPT-4.5

GPT-5.3-Codex

63%Vocabulary65%

16wSentence Length23w

0.57Hedging0.51

4.7Bold6.5

6.4Lists6.2

0.00Emoji0.16

1.30Headings1.90

0.54Transitions0.03

Based on 11 + 23 text responses

Research

What we learned reading every model

GPT-4.5 and GPT-5.3-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-5.3-Codex vs GPT-5Same lab

GPT-4.5 vs MiniMax M3New provider

GPT-4.5 vs Llama 4 MaverickNew provider

Updated Feb 2026

Our Verdict

GPT-5.3-Codex

GPT-4.5Runner-up

No community votes yet. On paper, GPT-5.3-Codex has the edge — newer, bigger context window.

GPT-5.3-Codex is 11x cheaper per token — worth considering if cost matters.

Too close to call

API pricing

Cost per 1M tokens

GPT-4.5

Input

$75.00

Output

$150.00

GPT-5.3-Codex

Input

$1.75

43× cheaper

Output

$14.00

11× cheaper

GPT-5.3-Codex is cheaper on both — 43× input, 11× output

Writing DNA

Style Comparison

Similarity

61%

GPT-5.3-Codex uses 15.8x more emoji

GPT-4.5

GPT-5.3-Codex

63%Vocabulary65%

16wSentence Length23w

0.57Hedging0.51

4.7Bold6.5

6.4Lists6.2

0.00Emoji0.16

1.30Headings1.90

0.54Transitions0.03

Based on 11 + 23 text responses

Research

What we learned reading every model

GPT-4.5 and GPT-5.3-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-5.3-Codex vs GPT-5Same lab

GPT-4.5 vs MiniMax M3New provider

GPT-4.5 vs Llama 4 MaverickNew provider