Side-by-side technical and economic comparison between xAI's Grok 4.6 and Google's Gemini 3.8 Pro.
| Metric | Grok 4.6 | Gemini 3.8 Pro | Advantage |
|---|---|---|---|
| Provider Organization | xAI | — | |
| Standard Input / 1M | $2.00 | $4.00 | Grok 4.6 (50% lower) |
| Cached Input / 1M | $0.50 | $0.40 | Gemini 3.8 Pro lower |
| Output / 1M | $6.00 | $18.00 | Grok 4.6 lower |
| Context Window | 500k | 1.05M | Gemini 3.8 Pro (1.05M) |
| Max Generation Tokens | 128k | 64k | Grok 4.6 |
| Tokenizer Family | xAI Byte-level BPE (~131k vocabulary) | Google Gemini SentencePiece (256k vocabulary) | — |
| Workload (per month) | Grok 4.6 | Gemini 3.8 Pro |
|---|---|---|
| Chatbot10k requests · 500 in / 200 out | $22.00 | $56.00 |
| RAG app100k requests · 8,000 in / 1,200 out | $2,320.00 | $5,360.00 |
| Coding agent100k requests · 12,000 in / 2,000 out | $3,600.00 | $8,400.00 |
Standard rates, no caching or batch discounts. Model your own numbers below.
Opt for Grok 4.6 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 $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.
At a typical 3:1 input-to-output token mix, Grok 4.6 is about 60% cheaper than Gemini 3.8 Pro. Grok 4.6 costs $2 per 1M input and $6 per 1M output tokens; Gemini 3.8 Pro costs $4 and $18.
Gemini 3.8 Pro has the larger context window: 1.05M tokens vs 500k.
Grok 4.6: yes, cached input costs $0.5/1M. Gemini 3.8 Pro: yes, cached input costs $0.4/1M.