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Claude Fable 5.1 API Pricing & Cost Calculator

Claude Fable 5.1 runs at $10 input / $50 output per 1M tokens with a 1M context window and 128K max output. Same headline rate as Claude Fable 5, but cached input drops to $0.25/1M — 4x cheaper than Claude Fable 5's $1.00, which is where the real saving is on repeated prompts. A 1,000-in / 500-out call costs $0.03500.

Anthropic plans to retire Claude Fable 5.1 on 2027-09-01

Pricing below is still current. Worth factoring the retirement date into anything you are building on it long-term.

Still available from Anthropic: Claude Fable 5, Claude Mythos 5, Claude Opus 5

Input
$10.00
per 1M tokens
Output
$50.00
per 1M tokens
Context window
1000K
tokens
Released
Cutoff
≈ Estimated tokenizer·$10.00 in·$50.00 out (per 1M)
Quick start with a use case
Total cost per call$0.0350
Input$0.0100
Output$0.0250
Cost comparison
Standard
$0.0350
With Caching
$0.0301
Save 14% ↓
With Batch
Not supported
Cutting costs? Open models start at $0.28/1M

DeepSeek, Kimi & 200+ open models on Novita AI — often 5–20x cheaper than proprietary APIs for comparable tasks.

Try Novita AI

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Detailed pricing

Claude Fable 5.1 pricing breakdown

All pricing dimensions including caching and batch discounts.

TypePrice (per 1M tokens)
Input$10.0000
Output$50.0000
Cached input$0.2500
Cache write$12.5000
Cutting costs? Open models start at $0.28/1M

DeepSeek, Kimi & 200+ open models on Novita AI — often 5–20x cheaper than proprietary APIs for comparable tasks.

Try Novita AI

Affiliate link — we may earn a commission at no extra cost to you.

Last verified 2026-09-05 · Anthropic official pricing · ⚠️ Spotted a wrong price? Report in 30s →

How it compares

Claude Fable 5.1 vs alternatives

Single-call cost (1000 input + 500 output tokens) ranked from cheapest.

ModelPer call
Claude Fable 5.1
Anthropic · this page
$0.0350
DeepSeek V3.2
DeepSeek
$0.000480
GPT-5.6 Luna
OpenAI
$0.000800
Gemini 3.1 Flash Lite
Google
$0.001000
DeepSeek V4-Flash
DeepSeek
$0.001100
GPT-5 mini
OpenAI
$0.001250
Recommended use

When to choose Claude Fable 5.1

Claude Fable 5.1 shines for complex multi-step reasoning, code generation and review, general-purpose tasks, long documents and large codebases, and image and document understanding. Token counts are estimated within ~10-20% margin.

Context window of 1000K tokens handles entire codebases or book-length documents.
Prompt caching available — significant savings for repeated system prompts.
Tool / function calling supported.
FAQ

Frequently asked questions

Claude Fable 5.1 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. A typical chat call (1000 input + 500 output tokens) costs approximately $0.0350. Use the calculator above to estimate your specific use case.
Claude Fable 5.1 supports a 1000K token context window with a max output of 128,000 tokens.
Yes. Cached input is priced at $0.25 per 1M tokens — 98% cheaper than uncached input. This is especially valuable for repeated system prompts, long-context retrieval, and chat threads with shared history.
Yes, Claude Fable 5.1 accepts image input. Vision token pricing is generally calculated based on image dimensions and folded into the input token count. Specific image-specific pricing varies — refer to Anthropic's official documentation.
Token counts for Claude Fable 5.1 are estimated from character ratios (~10-20% margin). Cost calculations use prices verified on 2026-09-05. For final billing accuracy, always verify with Anthropic's usage dashboard.
Claude Fable 5.1 does not currently support fine-tuning. Consider another model in the Anthropic family if fine-tuning is required.