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Gemini 3.1 Pro (Preview) vs Grok 4.6
A straight cost comparison of Gemini 3.1 Pro (Preview) (Google Gemini) and Grok 4.6 (xAI Grok), per 1,000,000 tokens, verified October 2026.
Rate-by-rate comparison
| Metric | Gemini 3.1 Pro (Preview) | Grok 4.6 | Winner |
|---|---|---|---|
| Input / 1M | $2 | $2 | Tie |
| Cached input / 1M | $0.20 | $0.50 | Gemini 3.1 Pro (Preview) |
| Cache write / 1M | — | — | Tie |
| Output / 1M | $12 | $6 | Grok 4.6 |
| Context window | 1,000,000 | 500,000 | Gemini 3.1 Pro (Preview) |
| Batch API | Yes | Yes | Tie |
| Long-context tier | > 200,000 | > 200,000 | — |
For per-token metrics, the lower number wins. For context window and batch support, the higher or broader option wins. A dash means the provider does not publish that rate: a missing cache-write fee means writes are not billed per token, while a missing cached-input rate means cache hits bill at the full input rate.
Blended cost: 1M input + 250K output
| Model | Blended cost | Difference |
|---|---|---|
| Gemini 3.1 Pro (Preview) | $5 | +$1.50 |
| Grok 4.6 | $3.50 | Cheaper |
Three workloads, two bills
| Workload | Gemini 3.1 Pro (Preview) | Grok 4.6 | Winner |
|---|---|---|---|
| Support chat 1,000 requests · 4K input / 600 output | $15.20 | $11.60 | Grok 4.6 |
| RAG with caching 1,000 requests · 50K input (45K cached) / 1K output | $31.08 | $38.57 | Gemini 3.1 Pro (Preview) |
| Nightly batch job 10,000 requests · 10K input / 2K output | $220 | $160 | Grok 4.6 |
Which one should you pick?
Gemini 3.1 Pro (Preview) wins on cached RAG, while Grok 4.6 wins on support chat, nightly batch job.
Beyond price, the two differ on output rate ($12 vs $6); cached-input rate ($0.20 vs $0.50); context window (1,000,000 vs 500,000).
Batch mode is available on Gemini 3.1 Pro (Preview) and Grok 4.6, which halves the nightly job. Both publish cached-input discounts, so a stable system prompt is worth caching on either.
FAQ
Is Gemini 3.1 Pro (Preview) cheaper than Grok 4.6?
On a blended 1M-input-plus-250K-output workload, Grok 4.6 is cheaper by 30% ($3.50 vs $5). The gap changes for cache-heavy prompts and for batch jobs, as the workload table shows.
Which handles longer prompts, Gemini 3.1 Pro (Preview) or Grok 4.6?
Grok 4.6 has the larger context window (1,000,000 vs 500,000 tokens). Watch the long-context threshold on Gemini 3.1 Pro (Preview) and Grok 4.6: rates rise once input passes it.
Do both models support prompt caching?
Gemini 3.1 Pro (Preview) bills cached reads at $0.20 per 1M; Grok 4.6 at $0.50.