Published rates rank differently once prompt caching, batch discounts and your own input-to-output ratio are applied. Run both against your numbers.
Claude Fable 5.1 vs Claude Opus 5.5
Whether Anthropic's top tier is worth 2.5x the price of Opus 5.5.
Monthly cost by workload shape
The same volume costs very different amounts depending on the shape of the traffic. No caching or batch applied.
| Workload | Claude Fable 5.1 | Claude Opus 5.5 | Difference | |
|---|---|---|---|---|
Customer support chatbot 50K/day · 800 in / 300 out | $35.0K | $14.0K | Claude Opus 5.5saves $21.0K | Model it → |
RAG / search answers 20K/day · 3000 in / 400 out | $30.4K | $12.2K | Claude Opus 5.5saves $18.3K | Model it → |
Agent / tool-use loop 8.0K/day · 2500 in / 600 out | $13.4K | $5,357.44 | Claude Opus 5.5saves $8,036.16 | Model it → |
Batch summarization 100K/day · 5000 in / 500 out | $228.3K | $91.3K | Claude Opus 5.5saves $137.0K | Model it → |
Code assistant 15K/day · 2000 in / 800 out | $27.4K | $11.0K | Claude Opus 5.5saves $16.4K | Model it → |
Frequently asked questions
Which is cheaper, Claude Fable 5.1 or Claude Opus 5.5?
At a typical 3:1 input-to-output ratio, Claude Opus 5.5 is cheaper: $8.00 blended per 1M tokens against $20.00. That holds at every input:output ratio, one model is cheaper on both rates.
What is the price difference between Claude Fable 5.1 and Claude Opus 5.5?
Claude Fable 5.1: $10.00 input, $50.00 output per 1M tokens. Claude Opus 5.5: $4.00 input, $20.00 output. That is 2.5x on input and 2.5x on output.
Does prompt caching change the answer?
Claude Fable 5.1 caches input at $0.250/1M and Claude Opus 5.5 caches at $0.200/1M. For input-heavy workloads with repeated context, caching can matter more than the base rate difference, model both in the calculator rather than comparing rate cards.
This page compares published prices only. It makes no claim about which model performs better on any task; that depends entirely on your evaluations.
Rate cards decide nothing on their own.
Most teams run several models at once. Finitizer Tokenomics shows what each one actually costs you, read from your own bills and exports, which workloads could test a smaller model, what they would cost on an open-weight model, and, for models you serve yourself, the cost per token beside the API price. A routing decision starts from your spend rather than a price page.
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