Claude Fable 5 vs Claude Opus 4.8 (Fast): API Cost Comparison
Compare the API pricing, context windows, features, and real-world cost projections for Claude Fable 5 (Anthropic) and Claude Opus 4.8 (Fast) (Anthropic). Use the interactive calculator below to compute your exact monthly cost based on your token usage and request volume.
Prices verified Jun 26, 2026
Interactive Cost Calculator
Fills in typical token counts for a workload type
Tokens in each prompt sent to the model
Tokens generated in each response
Total API calls per month
Showing costs for 2 models. Cheapest: Claude Fable 5 at $350.00/month.
| Alert | |||||||
|---|---|---|---|---|---|---|---|
BestClaude Fable 5 | Anthropic | $350.00 | $0.035000 | $100.00 | $250.00 | — | Alerts coming soon |
Claude Opus 4.8 (Fast) | Anthropic | $350.00 | $0.035000 | $100.00 | $250.00 | — | Alerts coming soon |
Monthly Cost Comparison
Price Comparison at a Glance
All prices are in USD per 1 million tokens ($/M tokens). Lower is cheaper.
| Pricing Type | Claude Fable 5 | Claude Opus 4.8 (Fast) | Cheaper |
|---|---|---|---|
| Input (standard) | $10.00/M | $10.00/M | — |
| Output | $50.00/M | $50.00/M | — |
Prices last verified: 2026-06-26
Cost Breakdown by Usage Volume
Estimated monthly costs at different request volumes, assuming 1,000 input tokens and 500 output tokens per request. Adjust in the calculator above for your specific use case.
| Volume | Claude Fable 5Monthly | Claude Opus 4.8 (Fast)Monthly | Claude Fable 5Per request | Claude Opus 4.8 (Fast)Per request |
|---|---|---|---|---|
| 1K requests/mo | $35.00 | $35.00 | $0.035000 | $0.035000 |
| 10K requests/mo | $350.00 | $350.00 | $0.035000 | $0.035000 |
| 100K requests/mo | $3,500.00 | $3,500.00 | $0.035000 | $0.035000 |
| 1M requests/mo | $35,000.00 | $35,000.00 | $0.035000 | $0.035000 |
Green values indicate the lower-cost option at each volume tier. Cost per request is calculated at 1,000 input + 500 output tokens using standard (non-batch, non-cached) pricing.
When to Choose Claude Fable 5
by Anthropic
- General chatbot
Input / 1M tokens
$10.00/M
Output / 1M tokens
$50.00/M
Context window
1,000,000
Tier
premium
When to Choose Claude Opus 4.8 (Fast)
by Anthropic
- General chatbot
Input / 1M tokens
$10.00/M
Output / 1M tokens
$50.00/M
Context window
1,000,000
Tier
premium
Key Differences Beyond Price
Cost is only one factor in choosing an AI model. Context window size, rate limits, supported features, and latency all affect whether a model fits your use case.
| Capability | Claude Fable 5 | Claude Opus 4.8 (Fast) |
|---|---|---|
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Max output tokens | 128,000 tokens | 128,000 tokens |
| Performance tier | Premium | Premium |
| Vision / image input | Yes | Yes |
| Function calling | Yes | Yes |
| JSON mode | Yes | Yes |
| Prompt caching | No | No |
| Batch API (50% discount) | No | No |
| Extended reasoning | Yes | Yes |
| Fine-tuning | No | No |
Frequently Asked Questions
Is Claude Fable 5 cheaper than Claude Opus 4.8 (Fast)?
Claude Fable 5 and Claude Opus 4.8 (Fast) cost the same at standard usage (1,000 input + 500 output tokens, 100K requests/month): $3,500.00/month each. For different token ratios, use the calculator above.
Which model has a larger context window, Claude Fable 5 or Claude Opus 4.8 (Fast)?
Both Claude Fable 5 and Claude Opus 4.8 (Fast) have the same context window: 1,000,000 tokens.
Do Claude Fable 5 and Claude Opus 4.8 (Fast) support the Batch API?
Neither Claude Fable 5 nor Claude Opus 4.8 (Fast) currently supports a batch API with discounted pricing. For batch-eligible alternatives, consider models from OpenAI, Anthropic, or Google that include batch API support.
Which model offers better prompt caching?
Neither Claude Fable 5 nor Claude Opus 4.8 (Fast) currently supports prompt caching. For prompt-caching capable alternatives, consider Claude models from Anthropic or GPT-4o from OpenAI.
What are the best use cases for Claude Fable 5 vs Claude Opus 4.8 (Fast)?
Both models are well-suited for General chatbot. Claude Fable 5 is particularly strong for overlapping tasks. Claude Opus 4.8 (Fast) is favored for similar workflows. At the same quality level, the lower-cost model is usually preferable; use this page's calculator to compare total monthly spend at your volume.
What is the cost per request for Claude Fable 5 vs Claude Opus 4.8 (Fast)?
At 1,000 input tokens and 500 output tokens per request — a typical conversational workload — Claude Fable 5 costs $0.035000 per request and Claude Opus 4.8 (Fast) costs $0.035000 per request. At 100,000 requests/month, that translates to $3,500.00 and $3,500.00 respectively. Use the interactive calculator to adjust these parameters for your actual workload.
Claude Fable 5 vs Claude Opus 4.8 (Fast): Summary
When comparing Claude Fable 5 and Claude Opus 4.8 (Fast) for API cost, the right choice depends on your workload's token profile, required features, and tolerance for latency. Both models cost the same at standard usage volumes (1,000 input + 500 output tokens per request at 100,000 requests/month) at $3,500.00/month.
Both models are priced in USD per million tokens, the standard unit across all major AI API providers. Claude Fable 5 charges $10.00/M for input tokens and $50.00/M for output tokens. Claude Opus 4.8 (Fast) charges $10.00/M input and $50.00/M output. If your workload is output-heavy (more tokens generated than consumed as input), the model with the lower output price compounds cost savings significantly at scale.
Context window capacity differs between the two: Both models support 1,000,000 tokens per request. A larger context window is essential for document summarization, large codebase analysis, and multi-document retrieval-augmented generation (RAG) applications.
Use the interactive calculator at the top of this page to enter your actual token usage and monthly request volume for a precise cost comparison tailored to your workload. Adjust for batch API discounts and prompt caching to find the most cost-effective option for your specific deployment.
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Relevant Use Cases
See cost recommendations for workloads where Claude Fable 5 or Claude Opus 4.8 (Fast) is recommended.