Side-by-side technical and economic comparison between xAI's Grok 2 mini and Google's Gemini 3.8 Pro.
• Grok 2 mini: Classified as a Legacy Reference model (Generally Available).
| Metric | Grok 2 mini | Gemini 3.8 Pro | Advantage |
|---|---|---|---|
| Provider Organization | xAI | — | |
| Standard Input / 1M | $0.20 | $4.00 | Grok 2 mini (95% lower) |
| Cached Input / 1M | None | $0.40 | Grok 2 mini lower |
| Output / 1M | $1.00 | $18.00 | Grok 2 mini lower |
| Context Window | 128k | 1.05M | Gemini 3.8 Pro (1.05M) |
| Max Generation Tokens | 8.2k | 64k | Gemini 3.8 Pro |
| Tokenizer Family | xAI Byte-level BPE (~131k vocabulary) | Google Gemini SentencePiece (256k vocabulary) | — |
Opt for Grok 2 mini when your engineering requirements prioritize xAI's ecosystem, specific tokenizer efficiencies (Calibrated xAI Tokenizer (±3%)), or when your expected prompt-to-completion ratios favor its $0.2/M input rate.
Opt for Gemini 3.8 Pro when looking for Google's tooling integration, specific context window depth (1.05M tokens), or when output generation volume favors its $18/M rate.