How much does Claude Fable 5.1 cost?

Claude Fable 5.1 costs $10 per 1 million input tokens and $50 per 1 million output tokens. This pricing is set by Anthropic.

What tokenizer does Claude Fable 5.1 use?

Claude Fable 5.1 uses the cl100k_base tokenizer. This tokenizer has a vocabulary of ~100,000 tokens and is widely used across many models.

What is Claude Fable 5.1's context window?

Claude Fable 5.1 supports a context window of 1.0M tokens (1,000,000 tokens). The maximum output length is 128K tokens.

How does Claude Fable 5.1 compare to other models?

You can compare Claude Fable 5.1's pricing and capabilities against other LLMs in the comparison table above, or visit the full pricing page for a side-by-side view of all models.

How do I count tokens for Claude Fable 5.1?

Use the token counter at the top of this page or visit the homepage calculator. Paste your text and it will show the exact token count and cost for Claude Fable 5.1 using the cl100k_base tokenizer.

Claude Fable 5.1

Last verified September 2, 2026 · Anthropic pricing ↗

$10.00/1M input · $50.00/1M output · 1.0M context · Anthropic

Count Tokens

Tokens

—

Input Cost

—

Output Cost

—

Tokens

—

Input Cost

—

Output Cost

Estimate Monthly Cost

Monthly Cost Estimator

Quick:

API calls / dayAvg input tokens / callAvg output tokens / call

<$0.0001/mo

Pick a preset above or enter custom usage

Alternatives to Claude Fable 5.1

Cheaper Alternative

o3 Deep Research

$10.00 in · $40.00 out · OpenAI

17% cheaper

Premium Upgrade

Gemini 3.1 Flash Image

$0.500 in · $60.00 out · Google

Premium tier from Google

Same Provider

Claude Fable 5

$10.00 in · $50.00 out · Anthropic

Higher tier in Anthropic ecosystem

Pricing Details

AnthropicAnthropic flagship, launched September 1, 2026 alongside Mythos 5.1. Base input, output and both cache writes are byte-identical to Fable 5: $10/$50, cache write (5min/1hr) $12.50/$20, batch $5/$25. The ONLY line that changed is the cache read, $1/MTok on Fable 5 to $0.25/MTok here. That is a 0.025x multiplier on base input where every other Claude model, all 15 other rows on Anthropic's price list, uses the standard 0.1x; Anthropic states the exception in a footnote and this is the first time it has broken the formula. Consequence: your saving over Fable 5 is exactly 0.75x the share of your bill that was cache reads, ceiling 75%. Anthropic's quoted 25% (typical) and 45% (highly agentic) decode to cache-read shares of 33.3% and 60%. Break-even is UNCHANGED at 1 read (5min) and 2 reads (1hr) because the write premium sets it and writes did not move. Write:read ratio went 12.5:1 to 50:1 (5min) and 20:1 to 80:1 (1hr), so a cache invalidation now costs 50 reads instead of 12.5 and the 1hr cache is 3.56x cheaper than the 5min across a sustained hour, up from 1.86x. Cache read is cheaper than Opus 5's $0.50 despite 2x the base price, and only 1.25x Sonnet 5's $0.20 on a 5x base. Multipliers stack: batch cache read $0.125, US-only inference_geo 1.1x makes it $0.275, Vertex/Bedrock regional endpoints carry the same 10% premium. Cache minimum 512 tokens. Full 1M context flat, no long-context surcharge. Live day one on Anthropic first-party, Bedrock, Vertex and Azure at identical rates. Anthropic-reported: Terminal-Bench-Science 0.1 52.6 (Fable 5 24.7, Opus 5 29.0), Terminal-Bench 4.0 55.8 (Fable 5 42.0, Opus 5 52.3, Mythos 5.1 60.9), GDPval-AA v2 1853 (Fable 5 1723, Opus 5 1824), OSWorld 2.0 77.9 partial / 41.7 strict, HLE 60.9 no tools / 65.0 with tools, AutomationBench 31.4, CursorBench 3.2.0 73.4. API ID: claude-fable-5-1.

Input / 1M tokens

$10

Output / 1M tokens

$50

Context Window

1.0M

Max Output

128K

Full Pricing Table Token Calculator

Price History

Launched at current price on 2026-09-01. No price changes recorded since.

Frequently Asked Questions

Common questions about Claude Fable 5.1 pricing and usage