About
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...
Related Models
Pricing
Input
$1.25
per 1M tokens
Output
$10.00
per 1M tokens
Blended
$3.44
per 1M tokens
Cheaper than 20% of models. Median price is $0.67/1M tokens.
Cost Calculator
Tokens per day1M
100K100M
Daily
$3.44
Monthly
$103.13
vs. Similar Models
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OpenAI: GPT-5.1-Codex
$3.440%
Performance
Context Window
128K
tokens
Larger than 16% of models
Max Output
32K
tokens
25% of context
Context Window Comparison
Inception: Mercury 2
128KSame
Perplexity: Sonar Reasoning Pro
128KSame
Upstage: Solar Pro 3
128KSame