OpenAI: GPT-5.1-Codex
OpenAI
OpenAI: GPT-5.1-Codex by OpenAI costs $1.25 per 1M input tokens and $10.00 per 1M output tokens, with a 400K-token context window.
Pricing
Input (per 1M tokens)
$1.25
Output (per 1M tokens)
$10.00
Cached input (per 1M)
$0.13
| Provider | Input / 1M | Output / 1M |
|---|---|---|
| OpenAI | $1.25 | $10.00 |
| openrouter | $1.25 | $10.00 |
Specifications
- Provider
- OpenAI
- Context window
- 400K tokens
- Parameters
- —
- Released
- Nov 2025
- Open weights
- No
- Frontier model
- No
Benchmarks
- LMArena WebDev Elo
- 1336.9
Speed & latency
Time to first token
1.79s
Output speed
122 tok/s
Fastest host: azure (via vercel-ai-gateway).
Compare OpenAI: GPT-5.1-Codex with…
OpenAI: GPT-5.1-Codex vs OpenAI: GPT-5.6 Sol Pro$10.00/1MOpenAI: GPT-5.1-Codex vs OpenAI: GPT-6.1 Sol Pro$10.00/1MOpenAI: GPT-5.1-Codex vs OpenAI: GPT-6.1 Sol Pro (batch)$5.00/1MOpenAI: GPT-5.1-Codex vs OpenAI: GPT-6.1 Sol$10.00/1MOpenAI: GPT-5.1-Codex vs OpenAI: GPT-6.1 Sol (batch)$5.00/1MOpenAI: GPT-5.1-Codex vs OpenAI: GPT-6 Luna Pro$0.50/1M
FAQ
How much does OpenAI: GPT-5.1-Codex cost?
OpenAI: GPT-5.1-Codex is priced at $1.25 per 1M input tokens and $10.00 per 1M output tokens. Output tokens cost more than input.
What is OpenAI: GPT-5.1-Codex's context window?
OpenAI: GPT-5.1-Codex supports a context window of 400K tokens — the maximum prompt plus response length it can handle in a single request.
Is OpenAI: GPT-5.1-Codex open weight?
No — OpenAI: GPT-5.1-Codex is a closed/proprietary model accessed via API.
Data as of 2026-10-14. Source: Pricing via OpenRouter API, openrouter.ai. Pricing is per 1M tokens (USD); confirm with the provider before production use.