Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | Phi-4 | Grok 4 Fast (Reasoning) |
|---|---|---|
| Input ($/M tokens) | $0.125 | $0.2 |
| Output ($/M tokens) | $0.5 | $0.5 |
Data from Artificial Analysis API — 12 benchmarks
Phi-4 is cheaper overall. Its blended price (3:1 input/output ratio) is $0.22/M tokens vs $0.28/M for Grok 4 Fast (Reasoning).
Grok 4 Fast (Reasoning) wins 11 out of 12 benchmarks compared to 1 for Phi-4. See the detailed benchmark chart above for per-category results.
Grok 4 Fast (Reasoning) generates tokens faster at 120 tok/s vs 37 tok/s. Phi-4 also has lower time-to-first-token (0.41s vs 4.60s).
Choose based on your priorities: Phi-4 for lower cost, Grok 4 Fast (Reasoning) for stronger benchmark performance, and Grok 4 Fast (Reasoning) for faster generation. For latency-sensitive apps, check the TTFT comparison above.