GPT-5.1-Codex-Mini has a larger context window than GPT-3.5 Turbo (400K tokens vs 16K tokens).
| Spec | GPT-3.5 Turbo | GPT-5.1-Codex-Mini |
|---|---|---|
| Input price | $1.5/M tokens | $1.5/M tokens |
| Output price | $2/M tokens | $6/M tokens |
| Context window | 16K tokens | 400K tokens |
| Weights | Closed | Closed |
| Free API (OpenRouter) | No | No |
| Released | Mar 2022 | Nov 2025 |
Not enough votes to call it. On the specs, GPT-5.1-Codex-Mini has the edge: bigger model tier, newer, bigger context window.
GPT-3.5 Turbo costs 3.0x less per token.
Reviewing agent-written code?See a Brief PR report
Per million tokens. Prices and uptime via OpenRouter, checked 13 Sep 2026.
GPT-5.1-Codex-Mini uses 10.4x more headings