GPT-5.5 vs Grok 4
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
GPT-5.5
77.2OpenAI · Apr 2026
OpenAI's flagship reasoning model with a 1M-token context window, built for hard coding, science and long-horizon agentic work.
Grok 4
xAI · Jul 2025
xAI's mid-2025 flagship, trained on the 200K-GPU Colossus cluster — a math and science reasoning standout of its generation.
The verdict
GPT-5.5 wins 3 of the 3 benchmarks these models share, against 0 for Grok 4. Grok 4 is about 1.9x cheaper per blended million tokens (3:1 input:output mix). GPT-5.5 also takes 1M of context versus 256K for Grok 4.
Benchmark head-to-head 3–0
Specs & pricing
| GPT-5.5 | Grok 4 | |
|---|---|---|
| modhub Index | 77.2 | — |
| Input price / 1M | $5 | $3 |
| Output price / 1M | $30 | $15 |
| Context window | 1M | 256K |
| Max output | 128K | — |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Jan 2026 | Jul 2025 |
| Released | Apr 2026 | Jul 2025 |
| Example monthly cost* | $95.00 | $52.50 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, GPT-5.5 or Grok 4?
- GPT-5.5 wins 3 of the 3 benchmarks these models share, against 0 for Grok 4. Grok 4 is about 1.9x cheaper per blended million tokens (3:1 input:output mix). GPT-5.5 also takes 1M of context versus 256K for Grok 4.
- Which is cheaper, GPT-5.5 or Grok 4?
- GPT-5.5 costs $5/$30 per million input/output tokens, while Grok 4 costs $3/$15. For a typical workload of 10M input and 1.5M output tokens per month, that's $95.00 versus $52.50.
- Which model is better for coding, GPT-5.5 or Grok 4?
- We don't yet track SWE-bench Verified results for both models; check their individual pages for coding-related scores.