Side-by-side technical and economic comparison between Google's Gemini 3.1 Pro and Anthropic's Claude Fable 5.1.
| Metric | Gemini 3.1 Pro | Claude Fable 5.1 | Advantage |
|---|---|---|---|
| Provider Organization | Anthropic | — | |
| Standard Input / 1M | $2.00 | $10.00 | Gemini 3.1 Pro (80% lower) |
| Cached Input / 1M | $0.20 | $0.25 | Gemini 3.1 Pro lower |
| Output / 1M | $12.00 | $50.00 | Gemini 3.1 Pro lower |
| Context Window | 2.10M | 200k | Gemini 3.1 Pro (2.10M) |
| Max Generation Tokens | 16.4k | 32.8k | Claude Fable 5.1 |
| Tokenizer Family | Google Gemini SentencePiece (256k vocabulary) | Anthropic Claude BPE (~65k vocabulary) | — |
Opt for Gemini 3.1 Pro when your engineering requirements prioritize Google's ecosystem, specific tokenizer efficiencies (Calibrated Gemini Tokenizer (±4%)), or when your expected prompt-to-completion ratios favor its $2/M input rate.
Opt for Claude Fable 5.1 when looking for Anthropic's tooling integration, specific context window depth (200k tokens), or when output generation volume favors its $50/M rate.