Claude Fable 5.1 vs GPT-5.4 Pro
Claude Fable 5.1 vs GPT-5.4 Pro: which AI model is cheaper, has the larger context window and more capabilities? Side-by-side comparison updated daily.
Quick verdict
- Claude Fable 5.1 is 3.4× cheaper than GPT-5.4 Pro for the same mix of input and output tokens.
- GPT-5.4 Pro has the larger context window (1.1M), useful for long documents and big codebases.
- Claude Fable 5.1 is the more recent release (Sep 1, 2026).
- Claude Fable 5.1 scores higher on independent tests (overall index 165.0 vs 159.1).
- Claude Fable 5.1 is both cheaper and better rated: for most uses it is the better choice.
| Claude Fable 5.1 | GPT-5.4 Pro | |
|---|---|---|
| Company | Anthropic | OpenAI |
| Released | Sep 1, 2026 ● | Mar 5, 2026 |
| Overall index | 165.0 ● | 159.1 |
| GPQA Diamond | — | 94.6% |
| AIME math | 100% | — |
| FrontierMath | 90.2% ● | 82.5% |
| SimpleQA Verified | 70.8% ● | 46.3% |
| Input (per 1M tokens) | $10 ● | $30 |
| Output (per 1M tokens) | $50 ● | $180 |
| Cost for 1M input + 1M output tokens | $60.00 ● | $210 |
| Providers | 4 ● | 3 |
| Context | 1M | 1.1M ● |
| Max output | 128K | 128K |
| Inputs | Text, Image, Files | Text, Image, Files |
| Outputs | Text | Text |
| Reasoning | ✓ | ✓ |
| Tool use | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Open weights | — | — |