GPT-5.3 Chat vs Grok 4.3
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for GPT-5.3 Chat and Grok 4.3.
GPT-5.3 Chat
GPT-5.3 Chat is an update to ChatGPT's most-used model that makes everyday conversations smoother, more useful, and more directly helpful. It delivers more accurate answers with better contextualization and significantly...
Grok 4.3
Grok 4.3 is a reasoning model from xAI. It accepts text and image inputs with text output, and is suited for agentic workflows, instruction-following tasks, and applications requiring high factual...
Technical Specifications
| Specification | GPT-5.3 Chat | Grok 4.3 |
|---|---|---|
| Provider | OpenAI | xAI |
| Context Window | 128,000 tokens | 1,000,000 tokens |
| Agent Suitability | N/A | 87/100 |
| Time to First Token (TTFT) | N/A | 400 ms |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2026-03-03 | 2026-04-30 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5.3 Chat
$1.75
Grok 4.3
$1.25
Output Price per Million Tokens
GPT-5.3 Chat
$14.00
Grok 4.3
$2.50
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
GPT-5.3 Chat Quirks & Gotchas
No developer gotchas reported.
Grok 4.3 Quirks & Gotchas
- ▸Strong coding performance — competitive with Claude Sonnet at similar price point
- ▸Upgrade to Grok 4.20 for improved reasoning and tool calling