Claude Fable 5.1 vs Gemini 3.5 Flash
Claude Fable 5.1 vs Gemini 3.5 Flash: which AI model is cheaper, has the larger context window and more capabilities? Side-by-side comparison updated daily.
Quick verdict
- Gemini 3.5 Flash is 5.9× cheaper than Claude Fable 5.1 for the same mix of input and output tokens.
- Gemini 3.5 Flash has the larger context window (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 154.6).
- Choose Gemini 3.5 Flash if cost matters most; choose Claude Fable 5.1 if you need its specific strengths above. For the best results, test both on your own prompts.
| Claude Fable 5.1 | Gemini 3.5 Flash | |
|---|---|---|
| Company | Anthropic | Google DeepMind |
| Released | Sep 1, 2026 ● | May 19, 2026 |
| Overall index | 165.0 ● | 154.6 |
| SWE-bench Verified | — | 79.3% |
| GPQA Diamond | — | 92.8% |
| AIME math | 100% ● | 95.6% |
| FrontierMath | 90.2% ● | 62.8% |
| SimpleQA Verified | 70.8% ● | 66.2% |
| Input (per 1M tokens) | $10 | $1.50 ● |
| Output (per 1M tokens) | $50 | $9 ● |
| Cost for 1M input + 1M output tokens | $60.00 | $10.50 ● |
| Providers | 4 | 7 ● |
| Context | 1M | 1M ● |
| Max output | 128K ● | 64K |
| Inputs | Text, Image, Files | Text, Image, Video, Files, Audio ● |
| Outputs | Text | Text |
| Reasoning | ✓ | ✓ |
| Tool use | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Open weights | — | — |