Side-by-side technical and economic comparison between Google's Gemini 3.8 Flash and xAI's Grok 4.6.
| Metric | Gemini 3.8 Flash | Grok 4.6 | Advantage |
|---|---|---|---|
| Provider Organization | xAI | — | |
| Standard Input / 1M | $0.75 | $2.00 | Gemini 3.8 Flash (63% lower) |
| Cached Input / 1M | $0.075 | $0.50 | Gemini 3.8 Flash lower |
| Output / 1M | $3.75 | $6.00 | Gemini 3.8 Flash lower |
| Context Window | 1.05M | 500k | Gemini 3.8 Flash (1.05M) |
| Max Generation Tokens | 16.4k | 128k | Grok 4.6 |
| Tokenizer Family | Google Gemini SentencePiece (256k vocabulary) | xAI Byte-level BPE (~131k vocabulary) | — |
Opt for Gemini 3.8 Flash 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 $0.75/M input rate.
Opt for Grok 4.6 when looking for xAI's tooling integration, specific context window depth (500k tokens), or when output generation volume favors its $6/M rate.