Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | Gemini 3.1 Pro Preview | Gemini 3 Flash Preview (Reasoning) |
|---|---|---|
| Input ($/M tokens) | $2 | $0.5 |
| Output ($/M tokens) | $12 | $3 |
Data from Artificial Analysis API — 12 benchmarks
Gemini 3 Flash Preview (Reasoning) is cheaper overall. Its blended price (3:1 input/output ratio) is $1.13/M tokens vs $4.50/M for Gemini 3.1 Pro Preview.
Gemini 3.1 Pro Preview wins 6 out of 12 benchmarks compared to 5 for Gemini 3 Flash Preview (Reasoning). See the detailed benchmark chart above for per-category results.
Gemini 3 Flash Preview (Reasoning) generates tokens faster at 180 tok/s vs 115 tok/s. However, Gemini 3 Flash Preview (Reasoning) has lower time-to-first-token (6.33s vs 31.49s).
Choose based on your priorities: Gemini 3 Flash Preview (Reasoning) for lower cost, Gemini 3.1 Pro Preview for stronger benchmark performance, and Gemini 3 Flash Preview (Reasoning) for faster generation. For latency-sensitive apps, check the TTFT comparison above.