GPT-4.5vsGPT-5
GPT-5 is cheaper than GPT-4.5 at $1.25/M vs $75/M input tokens.
| Spec | GPT-4.5 | GPT-5 |
|---|---|---|
| Input price | $75/M tokens | $1.25/M tokens |
| Output price | $150/M tokens | $10/M tokens |
| Context window | 128K tokens | 400K tokens |
| Parameters | Not disclosed | Not disclosed |
| Weights | — | Closed |
| Free API (OpenRouter) | No | No |
| Released | Feb 2025 | Aug 2025 |
| SWE-bench Verified | 28.0% | 74.9% |
Our Verdict
GPT-5
GPT-4.5Runner-up
Not enough votes to call it. On the specs, GPT-5 has the edge: newer, bigger context window.
GPT-5 wins Web Design and Image Generation. GPT-5 costs 15x less per token.
Slight edge
Reviewing agent-written code?See a Brief PR report
API pricing
Cost per 1M tokens
GPT-4.5
Input
$75.00
Output
$150.00
GPT-5
Input
$1.25
60× cheaper
Output
$10.00
15× cheaper
GPT-5 is cheaper on both: 60× input, 15× output.
Where to run it
2 hosts
GPT-4.5
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 13 Sep 2026.
Writing DNA
Style Comparison
Similarity
52%
GPT-4.5 uses 24.7x more bold
GPT-4.5
GPT-5
63%Vocabulary65%
16wSentence Length13w
0.57Hedging0.20
4.7Bold0.2
6.4Lists4.6
0.00Emoji0.00
1.30Headings0.16
0.54Transitions0.03
Based on 11 + 16 text responses
Research
What we learned reading every model
FAQ
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