Grok 4 vs GPT-5.5
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
|
by xAI
|
by OpenAI
|
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Jul 9, 2025 | Nov 15, 2025 |
| Pricing per million tokens | ||
| Input | $3.00/Mtok | $5.00/Mtok |
| Output | $15.00/Mtok | $30.00/Mtok |
| Blended avg | $9.00/Mtok | $17.50/Mtok |
| Cached input | — | $0.500/Mtok |
| Specifications | ||
| Context window | 256K tokens | 270K tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimage
|
textimageaudio
|
| Benchmarks from Vellum LLM Leaderboard | ||
| Avg benchmark score | 66.2 | 64 |
| Perf / dollar | 7.4 | 3.7 |
| GPQA Diamond | 75 | — |
| SWE-Bench | 55 | — |
| HumanEval | 87 | — |
| MATH 500 | 82 | — |
| Providers | ||
| Available from |
xAI — $3.00/$15.00/Mtok
|
OpenAI — $5.00/$30.00/Mtok
|
Cost at scale — 1M tokens (50/50 input/output)
| Volume | Grok 4 | GPT-5.5 | Savings |
|---|---|---|---|
| 1M tokens | $9 | $17.5 | $8.5 (48.6%) |
| 10M tokens | $90 | $175 | $85 (48.6%) |
| 100M tokens | $900 | $1750 | $850 (48.6%) |
| 1000M tokens | $9000 | $17500 | $8500 (48.6%) |
Summary
Grok 4 by xAI costs $3.00/Mtok input and $15.00/Mtok output, with a 256K-token context window. It supports text, image input.
GPT-5.5 by OpenAI costs $5.00/Mtok input and $30.00/Mtok output, with a 270K-token context window. It supports text, image, audio input.
On a blended cost basis, Grok 4 is 94.4% cheaper than GPT-5.5.
On benchmarks, Grok 4 scores higher (66.2 vs 64) on average. In terms of value, Grok 4 has better performance per dollar (7.4 vs 3.7).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.