Claude Opus 4vsMercury 2
Mercury 2 is cheaper than Claude Opus 4 at $0.25/M vs $15/M input tokens.
| Spec | Claude Opus 4 | Mercury 2 |
|---|---|---|
| Input price | $15/M tokens | $0.25/M tokens |
| Output price | $75/M tokens | $0.75/M tokens |
| Context window | 200K tokens | 128K tokens |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | May 2025 | Mar 2026 |
Our Verdict
Claude Opus 4
Mercury 2Runner-up
Not enough votes to call it. On the specs, Claude Opus 4 has the edge: bigger model tier, bigger context window, major provider backing.
Mercury 2 costs 100x less per token.
Too close to call
API pricing
Cost per 1M tokens
Claude Opus 4
Input
$15.00
Output
$75.00
Mercury 2
Input
$0.25
60× cheaper
Output
$0.75
100× cheaper
Mercury 2 is cheaper on both: 60× input, 100× output.
Where to run it
2 hosts
Claude Opus 41 host
Mercury 21 host
Per million tokens. Prices and uptime via OpenRouter, checked 9 Sep 2026.
Writing DNA
Style Comparison
Similarity
32%
Claude Opus 4 uses 14.5x more emoji
Claude Opus 4
Mercury 2
65%Vocabulary53%
57wSentence Length22w
0.67Hedging0.40
3.8Bold6.6
6.8Lists2.6
1.18Emoji0.08
1.42Headings0.87
0.22Transitions0.14
Based on 27 + 23 text responses
Research
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