Model comparison
GPT-5.5 Pro vs Claude Fable 5
Compare GPT-5.5 Pro vs Claude Fable 5 API pricing: input/output token costs, cache pricing, context windows, workload estimates, and routing fit.
GPT-5.5 Pro
openai · gpt-5.5-pro
- Input
- $30
- Output
- $180
- Context
- 1.1M
Claude Fable 5
anthropic · claude-fable-5
- Input
- $10
- Output
- $50
- Context
- 1M
Quick take
Claude Fable 5 has the lower input price at $10 per 1M input tokens. Claude Fable 5 is cheaper for the example blended workload below. GPT-5.5 Pro has the larger context window at 1.1M tokens.
Choose GPT-5.5 Pro if...
- GPT-5.5 Pro is safer for long documents, repository analysis, and RAG prompts because it has the larger context window.
Choose Claude Fable 5 if...
- Claude Fable 5 is the better default for cost-sensitive traffic and repeated high-volume calls.
Example workload cost
Estimates use input tokens plus 20% output tokens. They exclude provider discounts, cache hits, and tool/search surcharges.
| Workload | GPT-5.5 Pro | Claude Fable 5 | Cheaper |
|---|---|---|---|
| 1M input + 200K output | $66.00 | $20.00 | Claude Fable 5 |
| 10M input + 2M output | $660.00 | $200.00 | Claude Fable 5 |
| 100M input + 20M output | $6,600.00 | $2,000.00 | Claude Fable 5 |
Context, output, and capability fit
GPT-5.5 Pro provides the larger context window. Check max output separately when the task needs long reports, code generation, or full-document rewrites.
- GPT-5.5 Pro max output
- 128K
- Claude Fable 5 max output
- 128K
- GPT-5.5 Pro features
- prompt caching, function calling, vision
- Claude Fable 5 features
- prompt caching, function calling, vision
Risk notes for GPT-5.5 Pro
- High output price: cap max tokens for verbose generation workloads.
Risk notes for Claude Fable 5
- High output price: cap max tokens for verbose generation workloads.
Routing tags
frontierpremiumreasoningcodingagentslong-contextmultimodalcache-friendlyragmythos-class