GPT-5 mini vs Claude Fable 5.1
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | GPT-5 mini | Claude Fable 5.1 |
|---|---|---|
| Provider | OpenAI | Anthropic |
| Input Price (1M) | $0.25 | $10.00 |
| Output Price (1M) | $2.00 | $50.00 |
| Context Window | 128,000 | 1,000,000 |
Verdict
GPT-5 mini costs $0.25 per 1M input tokens and $2.00 per 1M output tokens. Claude Fable 5.1 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. GPT-5 mini is 98% cheaper on input tokens than Claude Fable 5.1. For output tokens, GPT-5 mini is the more affordable option at $2.00/1M vs $50.00.
On context window, Claude Fable 5.1 supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose GPT-5 mini
- ✓ You need the lowest input token cost ($ 0.25/1M)
- ✓ Your workload is output-heavy — GPT-5 mini generates text cheaper
- ✓ You are already integrated with OpenAI
When to choose Claude Fable 5.1
- ✓ 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 mini cheaper than Claude Fable 5.1? ▼
GPT-5 mini is cheaper on input tokens at $0.25/1M vs $10.00/1M for Claude Fable 5.1 — a 98% saving.
What is the context window of GPT-5 mini vs Claude Fable 5.1? ▼
GPT-5 mini has a 128,000-token context window. Claude Fable 5.1 has a 1,000,000-token context window. Claude Fable 5.1 supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: GPT-5 mini or Claude Fable 5.1? ▼
The best choice depends on your use case. For cost efficiency on input tokens, GPT-5 mini is the cheaper option. For maximum context length, Claude Fable 5.1 supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.