GPT-5 Pro vs Claude Fable 5
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | GPT-5 Pro | Claude Fable 5 |
|---|---|---|
| Provider | OpenAI | Anthropic |
| Input Price (1M) | $15.00 | $10.00 |
| Output Price (1M) | $120.00 | $50.00 |
| Context Window | 400,000 | 1,000,000 |
Verdict
GPT-5 Pro costs $15.00 per 1M input tokens and $120.00 per 1M output tokens. Claude Fable 5 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. Claude Fable 5 is 33% cheaper on input tokens than GPT-5 Pro. For output tokens, Claude Fable 5 is the more affordable option at $50.00/1M vs $120.00.
On context window, Claude Fable 5 supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose GPT-5 Pro
- ✓ You are already integrated with OpenAI
When to choose Claude Fable 5
- ✓ You need the lowest input token cost ($ 10.00/1M)
- ✓ Your workload is output-heavy — Claude Fable 5 generates text cheaper
- ✓ You need a larger context window (1,000,000 tokens)
- ✓ You are already integrated with Anthropic
Use the calculator above to simulate your specific workload and find the exact break-even point. For most applications, the cheapest model is the one that minimises your total monthly bill given your input-to-output token ratio.
Frequently Asked Questions
Is GPT-5 Pro cheaper than Claude Fable 5? ▼
Claude Fable 5 is cheaper on input tokens at $10.00/1M vs $15.00/1M for GPT-5 Pro — a 33% saving.
What is the context window of GPT-5 Pro vs Claude Fable 5? ▼
GPT-5 Pro has a 400,000-token context window. Claude Fable 5 has a 1,000,000-token context window. Claude Fable 5 supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: GPT-5 Pro or Claude Fable 5? ▼
The best choice depends on your use case. For cost efficiency on input tokens, Claude Fable 5 is the cheaper option. For maximum context length, Claude Fable 5 supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.