Very long inputs
Choose Grok 4.20 Reasoning
Grok 4.20 Reasoning reads up to 1M tokens per request, against 128k for GPT-5.3 Chat.
GPT-5.3 Chat vs Grok 4.20 Reasoning: price, context and capabilities
Choose Grok 4.20 Reasoning for very long inputs; on the other points the two are level or the data is missing.
In short
- A price comparison is not possible: one of them has no comparable published price.
- Grok 4.20 Reasoning reads more per request: 1M tokens against 128k.
- Only Grok 4.20 Reasoning offers prompt caching.
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Specifications side by side
| GPT-5.3 Chat | Grok 4.20 Reasoning | |
|---|---|---|
| Provider | OpenAI | xAI |
| Category | Language models | Language models |
| Status | Deprecated | Generally available |
| Headline price | No data | $1.56 / 1M tokens |
| Input | No data | $1.25 / 1M tokens |
| Output | No data | $2.50 / 1M tokens |
| Cached input | No data | $0.20 / 1M tokens |
| Context window | 128k | 1M |
| Max output | 16k | No data |
| Released | Mar 3, 2026 | March 2026 |
| Knowledge cutoff | August 2025 | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | gpt-5.3-chat-latest | grok-4.20-0309-reasoning |
Frequently asked questions
Should I choose GPT-5.3 Chat or Grok 4.20 Reasoning?
Choose Grok 4.20 Reasoning for very long inputs; on the other points the two are level or the data is missing.
Which is cheaper, GPT-5.3 Chat or Grok 4.20 Reasoning?
A price comparison is not possible: one of them has no comparable published price.
Which has the larger context window, GPT-5.3 Chat or Grok 4.20 Reasoning?
Grok 4.20 Reasoning reads more per request: 1M tokens against 128k.
What is the difference between GPT-5.3 Chat and Grok 4.20 Reasoning?
GPT-5.3 Chat is made by OpenAI and Grok 4.20 Reasoning by xAI. A price comparison is not possible: one of them has no comparable published price. Grok 4.20 Reasoning reads more per request: 1M tokens against 128k. Only Grok 4.20 Reasoning offers prompt caching.