GPT-5.3 Chat vs o3
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 o3.
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...
o3
o3 is a well-rounded and powerful model across domains. It sets a new standard for math, science, coding, and visual reasoning tasks. It also excels at technical writing and instruction-following....
Technical Specifications
| Specification | GPT-5.3 Chat | o3 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 128,000 tokens | 200,000 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2026-03-03 | 2025-04-16 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5.3 Chat
$1.75
o3
$2.00
Output Price per Million Tokens
GPT-5.3 Chat
$14.00
o3
$8.00
Want to test both models live?
Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.
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.
o3 Quirks & Gotchas
No developer gotchas reported.