Claude Fable 5.1 vs Claude Opus 5.5
Claude Fable 5.1 and Claude Opus 5.5 are Anthropic's top two. Claude Fable 5.1 lists at $10 / $50 per 1M tokens and Claude Opus 5.5 at $4 / $20.
Our verdict
Claude Opus 5.5 is the better default. It lists at less than half of Claude Fable 5.1's price, and Artificial Analysis ranks it higher (58 against 53, 1 Oct 2026 capture). On LiveBench the two are within 0.2 points (83.4 for Fable, 83.2 for Opus), and Anthropic reports 66.4% on Terminal-Bench 4.0 for Opus 5.5 against 55.8% for Fable 5.1 (Anthropic's own figures). Fable's cache discount does not close the gap, because Opus 5.5 cache reads cost $0.20 per 1M against Fable's $0.25. Pay for Fable only if your own test shows it winning.
Benchmarks measure test tasks, not your business. Run a real job through both models before you commit.
Side by side
| Claude Fable 5.1 | Claude Opus 5.5 | |
|---|---|---|
| Lab | Anthropic | Anthropic |
| List price per 1M tokens (input / output) | $10 / $50 | $4 / $20 |
| Scheduled price | - | - |
| Price notes | Cache reads $0.25 per 1M. | Cache reads $0.20 per 1M; fast mode $8 / $40. |
| Example job at list price | $20 | $8 |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Released | ||
| Open weights | No | No |
| Artificial Analysis Intelligence Index | 53 (Oct 1, 2026 capture) | 58 (Oct 1, 2026 capture) |
| LiveBench overall | 83.4 | 83.2 |
1M tokens in and 200K tokens out. List price only: models write different amounts, so a finished job can cost more or less. (1,000,000 / 200,000)
Common questions
Is Claude Fable 5.1 better than Opus 5.5?
Not on the independent index: Artificial Analysis scored Opus 5.5 58 and Fable 5.1 53 (1 Oct 2026 capture). On LiveBench Fable leads by 0.2 points (83.4 against 83.2).
How much more does Fable 5.1 cost?
It lists at $10 in and $50 out per 1M tokens against $4 and $20 for Opus 5.5, so our example job costs $20 against $8.
Why does Fable still exist?
Anthropic positions Fable as its top tier and sells it alongside Mythos 5.1. Since 22 September 2026 the cheaper Opus 5.5 has ranked higher on independent indexes, so Fable is no longer the default Claude pick.
Sources
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