Mercury 2.5 is cheaper than Claude Fable 5.1 at $0.04/M vs $10/M input tokens.
| Spec | Claude Fable 5.1 | Mercury 2.5 |
|---|---|---|
| Input price | $10/M tokens | $0.04/M tokens |
| Output price | $50/M tokens | $0.15/M tokens |
| Context window | 1.0M tokens | 260K tokens |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | Sep 2026 | Sep 2026 |
Not enough votes to call it. On the specs, Claude Fable 5.1 has the edge: bigger model tier, bigger context window, major provider backing.
Mercury 2.5 costs 333x less per token.
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Mercury 2.5 is cheaper on both: 250× input, 333× output.
Per million tokens. Prices and uptime via OpenRouter, checked 23 Sep 2026.