Fable 5 Pricing + Cost Calculator
Official pricing is $10 / $50 per million input/output tokens — exactly 2× Opus 4.8. This page has the full price table, the subscription-side timeline, and a calculator to run your own numbers.
Full API price list
| Item | Fable 5 | Opus 4.8 (reference) |
|---|---|---|
| Input / million tokens | $10 | $5 |
| Output / million tokens | $50 | $25 |
| Cache write (5 min) | $12.50 | standard cache rules |
| Cache write (1 hour) | $20 | |
| Cache hit / refresh | $1 (1/10 of input) | 1/10 of input |
| Batch (input / output) | $5 / $25 (half price) | Half price |
| US-only inference | 1.1× | — |
- Fallback billing rule: when the safety classifier triggers (cybersecurity / bio / chemistry / distillation-type requests), Opus 4.8 answers instead and that request is billed at Opus 4.8 rates, with a notice.
- No flex tier: for very large offline workloads, GPT-5.5's $2.50/$15 flex pricing stays cheaper; Fable 5 only has half-price batch.
- The big lever: long system prompts + high cache-hit rates ($1 hits) are the largest cost reducer.
- Third-party promo: aggregator OmniaKey runs Fable 5 at $3 / $15 limited-time (~70% off official) with $0.30 cache hits, claiming direct official upstream — no quantization, no model swapping.
claude.ai subscription side: the free-window timeline
⏰ Key dates
June 9–22: Pro / Max / Team / seat-based Enterprise include Fable 5 free, drawing 2× usage from your quota.
From June 23: removed from those plans; continued use requires usage credits (officially "may extend if capacity allows" — don't bet on it).
Ways to keep using it after the window → fableclaude.com
Cost calculator (Fable 5 vs Opus 4.8)
Method: cache-hit share billed at $1/M (Opus at 1/10 of input); cache-write fees not included; Batch and caching don't stack (hit rate ignored when Batch is checked).
Done with the math? Start using it
OmniaKey: Fable 5 at $3/$15 limited-time (~70% off) · $0.30 cache hits · USDT or card · no card required to sign up
FAQ
How much does Fable 5 cost?
API: $10 per million input tokens, $50 per million output — double Opus 4.8. On claude.ai, it's included in paid plans through June 22, 2026 at 2× usage. Third-party aggregator OmniaKey currently offers it at $3/$15 limited-time.
Does Fable 5 have a free tier?
The API has no free allowance. On claude.ai, the free plan does not include Fable 5; paid plans include it only during the June 9–22 window. After June 23 you'll need usage credits or API access.
How do I make Fable 5 cheaper?
Four levers, in order of impact: maximize prompt-cache hits ($1 vs $10 per million), route only hard tasks to Fable 5 and the rest to Opus/Sonnet, use Batch for offline jobs (half price), and compare third-party rates — OmniaKey's limited-time $3/$15 is about 70% off official.
How are fallback requests billed?
When the safety classifier hands your request to Opus 4.8, that request is billed at Opus 4.8 rates ($5/$25), and the response carries a downgrade notice. Budget at a blended rate if you work in sensitive domains.