GPT-4 Turbo vs GPT-5.1 Chat
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-4 Turbo and GPT-5.1 Chat.
GPT-4 Turbo
The latest GPT-4 Turbo model with vision capabilities. Vision requests can now use JSON mode and function calling. Training data: up to December 2023.
GPT-5.1 Chat
GPT-5.1 Chat (AKA Instant is the fast, lightweight member of the 5.1 family, optimized for low-latency chat while retaining strong general intelligence. It uses adaptive reasoning to selectively “think” on...
Technical Specifications
| Specification | GPT-4 Turbo | GPT-5.1 Chat |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 128,000 tokens | 128,000 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 | 2024-04-09 | 2025-11-13 |
API Pricing Comparison
Input Price per Million Tokens
GPT-4 Turbo
$10.00
GPT-5.1 Chat
$1.25
Output Price per Million Tokens
GPT-4 Turbo
$30.00
GPT-5.1 Chat
$10.00
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-4 Turbo Quirks & Gotchas
No developer gotchas reported.
GPT-5.1 Chat Quirks & Gotchas
No developer gotchas reported.