All six billing dimensions
Claude Fable 5.1 prices input, output, cache read, cache write (five-minute and one-hour tiers), and batch. List prices match Anthropic, AWS Bedrock, Microsoft Foundry and OpenRouter; Google Vertex carries an 11% premium reflecting the data-residency multiplier.
| Dimension | Claude Fable 5.1 | Claude Fable 5 | Notes |
|---|---|---|---|
| Input / 1M tokens | $10.00 | $10.00 | Identical across providers (Google Vertex +10%) |
| Output / 1M tokens | $50.00 | $50.00 | Identical across providers (Google Vertex +10%) |
| Cache read / 1M tokens | $0.25 | $1.00 | 75% reduction; the entire commercial case |
| Cache write 5-min / 1M | $12.50 | $12.50 | Break-even is a single re-read |
| Cache write 1-hour / 1M | $20.00 | $20.00 | For long-running agents |
| Batch input / output per 1M | $5.00 / $25.00 | $5.00 / $25.00 | Halves both directions |
The cache arithmetic, reproduced from the published rates
Cost equals uncached input times the input rate plus cached input times the cache-read rate plus output times the output rate. Cache WRITE cost is excluded because a long-running agent writes the prefix once and reads it many times; on a session with more than two reads the write is immaterial. State this assumption on the page.
| Workload profile | Input tokens | Cache hit rate | Output tokens | Fable 5.1 cost / task | Fable 5 cost / task | Saving % |
|---|---|---|---|---|---|---|
| A. Chat / short prompt, little reuse | 200,000 | 20% | 20,000 | $2.61 | $2.64 | 1.1% |
| B. Typical agentic session | 10,000,000 | 90% | 200,000 | $22.25 | $29.00 | 23.3% |
| C. Long-running cache-heavy agent | 20,000,000 | 95% | 100,000 | $19.75 | $34.00 | 41.9% |
What this reproduces
Profiles B and C reproduce Anthropic's "about 25% cheaper for typical workloads, up to about 45% for agentic work" claim from the published rates alone, which means OneInfer can state it as a verified calculation with its own method rather than as a vendor quote. Profile A is the honest counterweight: on short, low-reuse prompts the 75% cache cut is nearly invisible. Publishing profile A is what makes profiles B and C credible.
Ready to test the workflow?
Create account & add creditsCost per benchmark point
On cost per Terminal-Bench 4.0 point, Claude Opus 5 beats Claude Fable 5.1. Fable 5.1 buys the top score and the science capability, not the best value per point. A comparison page that concludes everything favours the newest model is not a comparison page and will not be cited.
| Model | Input $/1M | Output $/1M | Task cost | Terminal-Bench 4.0 | Cost per TB4.0 point |
|---|---|---|---|---|---|
| Claude Fable 5.1 | $10 | $50 | $2.00 | 55.8% | $0.0358 |
| Claude Fable 5 | $10 | $50 | $2.00 | 42.0% | $0.0476 |
| Claude Opus 5 | $5 | $25 | $1.00 | 52.3% | $0.0191 |
| Claude Mythos 5.1 | $10 | $50 | $2.00 | 60.9% | $0.0328 |
| GPT-5.6 Sol | $5 | $30 | $1.10 | 37.3% | $0.0295 |
Frequently asked questions
How much does Claude Fable 5.1 cost?
Claude Fable 5.1 costs $10 per 1M input tokens and $50 per 1M output tokens on OneInfer, matching Anthropic's list price. Cached input reads at $0.25 per 1M tokens, a 75% reduction from the $1.00 that Claude Fable 5 charges. Cache writes cost $12.50 per 1M for the five-minute tier and $20.00 for the one-hour tier. Batch requests halve both directions to $5.00 and $25.00.
Which is cheaper, Claude Fable 5.1 or Claude Fable 5?
It depends entirely on how much cached context you re-read per token generated, because list prices are identical at $10 per 1M input and $50 per 1M output. The only difference is the cache read rate, $0.25 against $1.00. On a short prompt at a 20% hit rate with little reuse, the saving is about 1% and not worth a migration. On a long-running agent at a 95% hit rate, total task cost falls from $34.00 to $19.75, a saving of about 42%.
Put Claude Fable 5.1 to work
Fund a controlled evaluation, start with a prepared prompt, and measure quality and cost on your own workload.