Claude Sonnet 4.5vsClaude Opus 4
Claude Sonnet 4.5 is cheaper than Claude Opus 4 at $3/M vs $15/M input tokens.
| Spec | Claude Sonnet 4.5 | Claude Opus 4 |
|---|---|---|
| Input price | $3/M tokens | $15/M tokens |
| Output price | $15/M tokens | $75/M tokens |
| Context window | 200K tokens | 200K tokens |
| Released | Sep 2025 | May 2025 |
| SWE-bench Verified | 77.2% | 72.5% |
Our Verdict
Claude Sonnet 4.5
Claude Opus 4
Not enough votes to call it. On the specs, nothing separates them.
Claude Sonnet 4.5 costs 5.0x less per token.
Too close to call
API pricing
Cost per 1M tokens
Claude Sonnet 4.5
Input
$3.00
5.0× cheaper
Output
$15.00
5.0× cheaper
Claude Opus 4
Input
$15.00
Output
$75.00
Claude Sonnet 4.5 is cheaper on both — 5.0× input, 5.0× output
Writing DNA
Style Comparison
Similarity
75%
Claude Opus 4 uses 2.9x more transitions
Claude Sonnet 4.5
Claude Opus 4
64%Vocabulary65%
94wSentence Length57w
0.48Hedging0.67
4.9Bold3.8
8.0Lists6.8
0.45Emoji1.18
1.91Headings1.42
0.07Transitions0.22
Based on 20 + 27 text responses
Research
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FAQ
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