Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | GPT-5.5 Instant (May 2026) | Grok 4 |
|---|---|---|
| Input ($/M tokens) | $5 | $5.5 |
| Output ($/M tokens) | $30 | $27.5 |
Data from Artificial Analysis API — 12 benchmarks
Grok 4 is cheaper overall. Its blended price (3:1 input/output ratio) is $11.00/M tokens vs $11.25/M for GPT-5.5 Instant (May 2026).
Grok 4 wins 7 out of 12 benchmarks compared to 5 for GPT-5.5 Instant (May 2026). See the detailed benchmark chart above for per-category results.
Both models have comparable generation speeds.
Choose based on your priorities: Grok 4 for lower cost, Grok 4 for stronger benchmark performance, and both have comparable speed. For latency-sensitive apps, check the TTFT comparison above.