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) | — |
| Workload (per month) | Gemini 3.8 Flash | Grok 4.6 |
|---|---|---|
| Chatbot10k requests · 500 in / 200 out | $11.25 | $22.00 |
| RAG app100k requests · 8,000 in / 1,200 out | $1,050.00 | $2,320.00 |
| Coding agent100k requests · 12,000 in / 2,000 out | $1,650.00 | $3,600.00 |
Standard rates, no caching or batch discounts. Model your own numbers below.
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.
At a typical 3:1 input-to-output token mix, Gemini 3.8 Flash is about 50% cheaper than Grok 4.6. Gemini 3.8 Flash costs $0.75 per 1M input and $3.75 per 1M output tokens; Grok 4.6 costs $2 and $6.
Gemini 3.8 Flash has the larger context window: 1.05M tokens vs 500k.
Gemini 3.8 Flash: yes, cached input costs $0.075/1M. Grok 4.6: yes, cached input costs $0.5/1M.