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Claude Fable 5 API Pricing & Cost Calculator

Fable 5 belongs in the 'use only when Opus 5 isn't enough' tier. At double Opus 5's rates it only earns its keep on the hardest agentic chains, where the 90% cache discount can still bail you out.

Claude Fable 5 is Anthropic's most expensive reasoning tier, sitting above Opus 5 in their lineup. It targets the hardest multi-step agentic chains where Opus 5 still occasionally stalls.

By TechCompare · Updated

Input tokens
100,000
per request
Output tokens
5,000
per request
Volume
100 / monthly
Standard API

Calculator

Cost Comparison

Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.Prices are fetched live from OpenRouter and may include temporary promotional discounts not accounted for in our article and comparison figures.

Same 100,000 in / 5,000 out (50% cached) scenario, pre-loaded. Adjust tokens, caching, or swap models.
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How this is calculated

Claude Fable 5 is priced at $10.00 per million input tokens and $50.00 per million output tokens - double Claude Opus 5's rate. It supports a 90% prompt caching discount ($1.00 per million cached reads) and a 50% batch discount ($5.00 per million inputs, $25.00 per million outputs) via Anthropic's Message Batches API.

Verdict

At $10/M input and $50/M output Fable 5 charges twice Opus 5's rate, with the 90% cache discount still landing cached input at $1.00/M and the 50% batch discount taking both rows to $5/M input and $25/M output. That's a $5/M input gap on Opus 5 even after both discounts apply, so the only cost lever that closes it is the cache discount on stable-prompt loops where the cached input rate is what matters and the per-call total counts. Route the work that Opus 5 stalls on and nothing else, because the price gap dwarfs the quality gap on most workloads.

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Frequently asked questions

Is Claude Fable 5 worth it over Claude Opus 5?
Only for the hardest agentic chains where Opus 5's reasoning falls short. Fable 5 costs double across the board ($10 vs $5 input, $50 vs $25 output), so reserve it for cases where the quality delta justifies the bill.
How much does Claude Fable 5 cost per million output tokens?
Claude Fable 5 charges $50.00 per million output tokens at standard pricing, double Opus 5's $25/M. With the 50% batch discount, that drops to $25.00 per million. The 90% prompt caching discount brings cached input to $1.00 per million, useful for repetitive hardest-tier agentic chains where most context is cached.
When does Claude Fable 5 justify its 2x premium over Opus 5?
Only on the very hardest agentic chains where Opus 5's reasoning demonstrably stalls. Fable 5 is positioned as the rare-tier model for tasks like multi-step scientific research, deep multi-file code synthesis with novel reasoning, and complex planning that exceeds Opus 5. The quality jump must justify the cost. Otherwise, you're overpaying.

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