GPT-5.5 vs Grok Code Fast 1
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 Code Fast 1
xAI · Aug 2025
A speed-first coding model built for agentic IDE loops, popular as a cheap fast tier in Cursor and similar tools.
The verdict
GPT-5.5 wins 1 of the 1 benchmarks these models share, against 0 for Grok Code Fast 1. On price the gap is dramatic: Grok Code Fast 1 works out roughly 21x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 256K for Grok Code Fast 1.
Benchmark head-to-head 1–0
Specs & pricing
| GPT-5.5 | Grok Code Fast 1 | |
|---|---|---|
| modhub Index | 77.2 | — |
| Input price / 1M | $5 | $0.2 |
| Output price / 1M | $30 | $1.5 |
| Context window | 1M | 256K |
| Max output | 128K | — |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text |
| Knowledge cutoff | Jan 2026 | Aug 2025 |
| Released | Apr 2026 | Aug 2025 |
| Example monthly cost* | $95.00 | $4.25 |
* 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 Code Fast 1?
- GPT-5.5 wins 1 of the 1 benchmarks these models share, against 0 for Grok Code Fast 1. On price the gap is dramatic: Grok Code Fast 1 works out roughly 21x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 256K for Grok Code Fast 1.
- Which is cheaper, GPT-5.5 or Grok Code Fast 1?
- GPT-5.5 costs $5/$30 per million input/output tokens, while Grok Code Fast 1 costs $0.2/$1.5. For a typical workload of 10M input and 1.5M output tokens per month, that's $95.00 versus $4.25.
- Which model is better for coding, GPT-5.5 or Grok Code Fast 1?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus 70.8% for Grok Code Fast 1, making GPT-5.5 the stronger pick for coding agents.