Gemini 2.5 Flash 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 Gemini 2.5 Flash and GPT-5.1 Chat.
Gemini 2.5 Flash
Gemini 2.5 Flash is Google's state-of-the-art workhorse model, specifically designed for advanced reasoning, coding, mathematics, and scientific tasks. It includes built-in "thinking" capabilities, enabling it to provide responses with greater...
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 | Gemini 2.5 Flash | GPT-5.1 Chat |
|---|---|---|
| Provider | OpenAI | |
| Context Window | 1,048,576 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 | beta | stable |
| API Available | Yes | Yes |
| Released Date | 2025-06-17 | 2025-11-13 |
API Pricing Comparison
Input Price per Million Tokens
Gemini 2.5 Flash
$0.30
GPT-5.1 Chat
$1.25
Output Price per Million Tokens
Gemini 2.5 Flash
$2.50
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.
Gemini 2.5 Flash Quirks & Gotchas
No developer gotchas reported.
GPT-5.1 Chat Quirks & Gotchas
No developer gotchas reported.