Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | Gemini 2.5 Flash Preview (Reasoning) | o3 |
|---|---|---|
| Input ($/M tokens) | $0 | $2 |
| Output ($/M tokens) | $0 | $8 |
Data from Artificial Analysis API — 12 benchmarks
Gemini 2.5 Flash Preview (Reasoning) is cheaper overall. Its blended price (3:1 input/output ratio) is $0.00/M tokens vs $3.50/M for o3.
o3 wins 11 out of 12 benchmarks compared to 0 for Gemini 2.5 Flash Preview (Reasoning). See the detailed benchmark chart above for per-category results.
o3 generates tokens faster at 125 tok/s vs 0 tok/s. Gemini 2.5 Flash Preview (Reasoning) also has lower time-to-first-token (0.00s vs 6.65s).
Choose based on your priorities: Gemini 2.5 Flash Preview (Reasoning) for lower cost, o3 for stronger benchmark performance, and o3 for faster generation. For latency-sensitive apps, check the TTFT comparison above.