Claude Fable 5.1 API Pricing and Cost Estimates
Anthropic Claude Fable 5.1 API pricing is $10 per 1M input tokens and $50 per 1M output tokens. Cached input is billed at $0.25 per 1M tokens. The context window is 1M tokens. The Batch API bills at 50% of standard. Prices verified 2026-09-04 against the official pricing page.
Input / 1M tokens
$10
Output / 1M tokens
$50
Cached input / 1M
$0.25
Context window
1M
Monthly cost at three workloads
| Workload | Tokens / month | Standard | 50% cache hit | Batch API |
|---|---|---|---|---|
| Light (prototype / side project) | 5M in + 1M out | $100 | $75.63 | $50.00 |
| Medium (small production app) | 50M in + 10M out | $1000 | $756 | $500 |
| Heavy (production at scale) | 500M in + 100M out | $10,000 | $7563 | $5000 |
Note: Released Sep 1, 2026. Anthropic's Mythos-class flagship tier above Opus 5 — same $10/$50 base rate as Fable 5, but cache reads drop to 2.5% of the input price ($0.25/MTok vs the 10% every other Claude model charges). Shares its underlying model with Claude Mythos 5.1, offered only to approved organizations.
Closest-priced alternatives
| Model | Input / 1M | Output / 1M | Medium workload / mo |
|---|---|---|---|
| Anthropic Claude Fable 5.1 | $10 | $50 | $1000 |
| Anthropic Claude Fable 5 | $10 | $50 | $1000 |
| Anthropic Claude Opus 5 | $5 | $25 | $500 |
| OpenAI GPT-5.6 sol | $4 | $20 | $400 |
| Moonshot Kimi K3 | $3 | $15 | $300 |
Medium workload = 50M input + 10M output tokens per month at standard price, no caching. Prices verified 2026-09-04.
Claude Fable 5.1 vs the rest of the Anthropic lineup
| Model | Input / 1M | Output / 1M | Cached / 1M | Context | Medium workload / mo |
|---|---|---|---|---|---|
| Claude Fable 5.1 | $10 | $50 | $0.25 | 1M | $1000 |
| Claude Fable 5 | $10 | $50 | $1 | 1M | $1000 |
| Claude Opus 5 | $5 | $25 | $0.5 | 1M | $500 |
| Claude Sonnet 5 | $2 | $10 | $0.2 | 1M | $200 |
| Claude Haiku 4.5 | $1 | $5 | $0.1 | 200K | $100 |
Calculate with your own volume
LLM API Pricing Calculator
Compare current API prices for Claude, GPT, Gemini, DeepSeek, Kimi, Grok and other LLMs, and estimate your monthly bill from token volume. Includes prompt-caching prices and batch discounts that most comparison tables miss. Prices last verified 2026-09-04. Runs entirely in your browser — no upload, no signup.
Share of input tokens served from prompt cache
| Model | Input $/M | Output $/M | Cached $/M | Context | Est. monthly |
|---|---|---|---|---|---|
GPT-5.6 luna OpenAI | $0.2 | $1.2 | $0.02 | 1.05M | $22.00 |
Gemini 3.1 Flash-Lite | $0.25 | $1.5 | $0.025 | 1M | $27.50 |
DeepSeek V4 Flash DeepSeek · open-weight | $0.435 | $1.3 | $0.0145 | 1M | $34.75 |
Gemini 3.6 Flash | $0.75 | $3.75 | $0.075 | 1M | $75.00 |
GLM-5 Zhipu (z.ai) · open-weight | $1 | $3.2 | $0.2 | 200K | $82.00 |
Grok 4.20 xAI | $1.25 | $2.5 | $0.2 | 1M | $87.50 |
Kimi K2.7 Code Moonshot · open-weight | $0.95 | $4 | $0.19 | 262K | $87.50 |
Claude Haiku 4.5 Anthropic | $1 | $5 | $0.1 | 200K | $100 |
DeepSeek V4 Pro DeepSeek · open-weight | $1.3 | $3.91 | $0.043 | 1M | $104 |
GLM-5.2 Zhipu (z.ai) · open-weight | $1.4 | $4.4 | $0.26 | 200K | $114 |
Grok 4.6 xAI | $2 | $6 | $0.5 | 500K | $160 |
Grok 4.5 xAI | $2 | $6 | $0.3 | 500K | $160 |
Claude Sonnet 5 Anthropic | $2 | $10 | $0.2 | 1M | $200 |
GPT-5.6 terra OpenAI | $2 | $12 | $0.2 | 1.05M | $220 |
Gemini 3.1 Pro Preview | $2 | $12 | $0.2 | 1M | $220 |
Kimi K3 Moonshot · open-weight | $3 | $15 | $0.3 | 1.048576M | $300 |
GPT-5.6 sol OpenAI | $4 | $20 | $0.4 | 1.05M | $400 |
Claude Opus 5 Anthropic | $5 | $25 | $0.5 | 1M | $500 |
Claude Fable 5.1 Anthropic | $10 | $50 | $0.25 | 1M | $1000 |
Claude Fable 5 Anthropic | $10 | $50 | $1 | 1M | $1000 |
Prices are per 1 million tokens in USD, standard (non-batch) tier, verified 2026-09-04 against official pricing pages. Claude Fable 5.1: Released Sep 1, 2026. Anthropic's Mythos-class flagship tier above Opus 5 — same $10/$50 base rate as Fable 5, but cache reads drop to 2.5% of the input price ($0.25/MTok vs the 10% every other Claude model charges). Shares its underlying model with Claude Mythos 5.1, offered only to approved organizations. Claude Fable 5: Superseded by Claude Fable 5.1 (Sep 1, 2026), which keeps the same base rate but cuts cache reads to $0.25/MTok. Fable 5 remains available as a pinned snapshot with cache reads at the standard 10% ($1.00/MTok). Shares its underlying model with Claude Mythos 5. Claude Sonnet 5: The $2 / $10 launch price is now permanent; the planned Sep 2026 increase to $3 / $15 was cancelled. GPT-5.6 sol: Promotional price, available at least through Nov 21, 2026 (previously $5 / $30). Requests beyond the long-context threshold bill at 2× input / 1.5× output. GPT-5.6 terra: Requests beyond the long-context threshold bill at 2× input / 1.5× output. GPT-5.6 luna: Requests beyond the long-context threshold bill at 2× input / 1.5× output. Gemini 3.1 Pro Preview: Prompts over 200K tokens bill at $4 / $18. Gemini 3.6 Flash: Intro price through Dec 31, 2026; $1.50 / $7.50 from Jan 1, 2027. Grok 4.6: Requests over 200K tokens bill at 2×. Grok 4.5: Requests over 200K tokens bill at 2×. Kimi K3: Always-on reasoning; output includes thinking tokens. DeepSeek V4 Pro: Peak-hour price (Beijing weekdays 09:00–12:00, 14:00–18:00) effective Aug 17, 2026; all other hours bill at 50% of peak. DeepSeek V4 Flash: Peak-hour price (Beijing weekdays 09:00–12:00, 14:00–18:00) effective Aug 17, 2026; all other hours bill at 50% of peak.
Batch discount is applied only to models whose provider offers an async batch tier. Cached-input pricing models the read price; cache-write surcharges (Anthropic) are not included. Long-context surcharges apply above provider thresholds and are noted per model.
FAQ
How much does the Claude Fable 5.1 API cost?
$10 per 1M input tokens and $50 per 1M output tokens, with cached input at $0.25 per 1M. Note: Released Sep 1, 2026. Anthropic's Mythos-class flagship tier above Opus 5 — same $10/$50 base rate as Fable 5, but cache reads drop to 2.5% of the input price ($0.25/MTok vs the 10% every other Claude model charges). Shares its underlying model with Claude Mythos 5.1, offered only to approved organizations. (Verified 2026-09-04.)
What does a month of Claude Fable 5.1 cost in practice?
A medium workload of 50M input + 10M output tokens per month runs about $1000/mo, or about $756/mo if half the input hits the prompt cache. Offline jobs can use the Batch API at 50% of standard.
How does prompt caching change Claude Fable 5.1 pricing?
Input tokens served from the prompt cache bill at $0.25 per 1M — about 3% of the standard input price. Repeated prefixes like system prompts and few-shot examples benefit most.
Is Claude Fable 5.1 cheaper than Claude Fable 5?
At the same medium workload, Claude Fable 5.1 costs about $1000/mo versus about $1000/mo for Anthropic Claude Fable 5. Also weigh quality, latency, and context window (1M vs 1M tokens).
How does Claude Fable 5.1 pricing compare with other Anthropic models?
By input price: Claude Fable 5 is $10/$50 per 1M tokens in/out (about 100% of Claude Fable 5.1's input price); Claude Opus 5 is $5/$25 per 1M tokens in/out (about 50% of Claude Fable 5.1's input price); Claude Sonnet 5 is $2/$10 per 1M tokens in/out (about 20% of Claude Fable 5.1's input price); Claude Haiku 4.5 is $1/$5 per 1M tokens in/out (about 10% of Claude Fable 5.1's input price). See the full-lineup table above.