GPT-5.5 Pro vs Grok 4.5
GPT-5.5 Pro and Grok 4.5 are both current production-tier models. Grok 4.5 is meaningfully cheaper at $2 / $6 per 1M. GPT-5.5 Pro leads on reasoning, general knowledge, long-context retrieval.
Specs side by side
| Metric | OpenAI GPT-5.5 Pro | xAI Grok 4.5 |
|---|---|---|
| Input price (per 1M) | $30 | $2 |
| Output price (per 1M) | $180 | $6 |
| Context window | 400k tokens | 500k tokens |
| Speed tier | slow | balanced |
| Open weights | No | No |
| EU region | No | No |
| Free tier | No | No |
| Prompt caching | Yes | Yes |
| Vision input | Yes | Yes |
| Extended thinking | Yes | Yes |
When to choose each
Choose GPT-5.5 Pro if…
- HIPAA eligibility is required
- Reasoning is central to your workload
- General knowledge is central to your workload
Choose Grok 4.5 if…
- Cost is a priority ($2 / $6 per 1M vs $30 / $180 per 1M)
Benchmark delta
GPT-5.5 Pro leads on
- Reasoning
- General knowledge
- Long-context retrieval
- Multilingual
- Vision
Grok 4.5 leads on
Grok 4.5 has no meaningful benchmark lead in this pair.
FAQ — GPT-5.5 Pro vs Grok 4.5
GPT-5.5 Pro vs Grok 4.5 — which is better?
GPT-5.5 Pro and Grok 4.5 are both current production-tier models. Grok 4.5 is meaningfully cheaper at $2 / $6 per 1M. GPT-5.5 Pro leads on reasoning, general knowledge, long-context retrieval. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.
How does GPT-5.5 Pro pricing compare to Grok 4.5?
GPT-5.5 Pro costs $30 / $180 per 1M vs Grok 4.5 at $2 / $6 per 1M. Grok 4.5 is cheaper on output tokens by roughly 2900%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.
Does GPT-5.5 Pro or Grok 4.5 have the bigger context window?
Grok 4.5 has a 500k-token context window — 1× the 400k context of GPT-5.5 Pro. Enough for long reports and multi-document analysis.
Is there a free tier for GPT-5.5 Pro or Grok 4.5?
GPT-5.5 Pro: no — Paid-only — no free tier. Grok 4.5: no — X Premium / SuperGrok includes Grok web chat; API is paid.
Which is better for coding — GPT-5.5 Pro or Grok 4.5?
GPT-5.5 Pro leads on coding benchmarks (GPT-5.5 Pro: 96/100, Grok 4.5: 94/100). For production coding agents also weigh tool-use performance — GPT-5.5 Pro scores 94, Grok 4.5 scores 92.