How much does GPT-5.1-Codex cost per million tokens?

GPT-5.1-Codex costs $1.25 per million input tokens and $10 per million output tokens at list price, and $0.13 per million cached input tokens.

What is the context window of GPT-5.1-Codex?

GPT-5.1-Codex accepts up to 400,000 tokens of context and returns up to 128,000 output tokens.

How much do 1,000 chat messages cost with GPT-5.1-Codex?

About $6.25, assuming 1,000 input + 500 output tokens per message.

Is there a cheaper alternative to GPT-5.1-Codex?

In the same price range, SpaceXAI Grok 4.7 ($2 / $6), Qwen Qwen3.8 Omni Flash ($0.15 / $0.47), Z.ai GLM 5.3 FlashX ($0.37 / $1.25) cost less per token. Quality differs: test on your own prompts.

Where can I buy OpenAI API credits for less?

Discount credit books resell OpenRouter usage below face value within their depth, OpenRouter adds a 5.5% card fee, and OpenAI sells its own credits at face value. The live table on this page ranks them for $100 of usage.

OpenAI · live price

GPT-5.1-Codex API pricing

GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks....

Mid-range ($1–5 per 1M)Tool callingReasoningimage input

Input: $1.25; per 1M tokens
Output: $10; per 1M tokens
Cached input: $0.13; per 1M tokens
Context: 400K; 128K max output

List price from OpenRouter, which passes OpenAI's price through without markup. Refreshed hourly. Released November 13, 2025. Model id openai/gpt-5.1-codex.

What GPT-5.1-Codex costs in practice

At list price, before any batch or caching discount.

1,000 chat messages

$6.25

1,000 input + 500 output tokens each

1,000 RAG questions

$15.00

8,000 input + 500 output tokens each

100 coding-agent steps

$5.75

30,000 input + 2,000 output tokens each, no caching

GPT-5.1-Codex price history

No price change since we started tracking on 2026-10-01. We record prices daily; changes will show here.

GPT-5.1-Codex price by host

One host serves this model through OpenRouter.

Azure$1.25 in · $10 out · 400K ctx · 100.0% uptime 24h

Where to buy OpenAI credits for less

GPT-5.1-Codex costs the same per token everywhere it's sold through OpenRouter. What changes is the price of the credits. Live quotes for $100 of usage:

#	Where you buy	You payYou pay for $100.00 of usage	vs list price	Price source
1	OrbioCardCheapest right now Credits from a discount book, plus a 5% platform fee and card processing, both included in the quote.	$85.10 incl. $2.60 card processing	-14.9%	live quote
2	smaaartCard Credits from a discount book, plus a 5% platform fee on face value. Card processing and taxes shown at checkout.	$95.00 + card processing and tax at checkout (not in this number)	-5.0%	live quote
3	Direct from the labCard Prepaid credits at face value (OpenAI, Anthropic, Google…). Taxes may apply.	$100.00 no top-up fee	list price	face value
4	OpenRouterCrypto 5% on crypto purchases. No markup on model prices.	$105.00 fees included	+5.0%	published fee
5	OpenRouterCard 5.5% on card purchases, $0.80 minimum. No markup on model prices.	$105.50 fees included	+5.5%	published fee

Disclosure: this site is run by the team behind smaaart, one of the options compared. Tables are ranked by price only, from live quotes and published fees, including when smaaart isn't first. How we compare

GPT-5.1-Codex cost calculator

Enter your monthly tokens to price your own usage.

Model$1.25 in / $10.00 out per 1M tokens · list price, liveInput tokens / month (millions)Output tokens / month (millions)

Usage at list price$162.50/ month(quotes below are for $163.00: purchases run from $5.00 to $10,000.00)

Cheaper alternatives to GPT-5.1-Codex

Other labs' models in the same price range or the one below, cheaper per token.

Model	Input / 1M	Output / 1M	Blended 3:1	Context
SpaceXAI: Grok 4.7	$2	$6	$3	500K
Qwen: Qwen3.8 Omni Flash	$0.15	$0.47	$0.23	1M
Z.ai: GLM 5.3 FlashX	$0.37	$1.25	$0.59	1.0M
DeepSeek: DeepSeek V4.1 Flash	$0.03	$0.5	$0.147	1.0M
Qwen: Qwen3.8 Max (0902)	$2	$6	$3	1M
Google: Gemini 3.8 Flash	$0.75	$3.75	$1.50	1.0M

Other OpenAI models

Model	Input / 1M	Output / 1M	Blended 3:1	Context
GPT-5.1	$1.25	$10	$3.44	400K
GPT-5.1-Codex-Mini	$0.25	$2	$0.688	400K
gpt-oss-safeguard-20b	$0.075	$0.3	$0.131	131K
GPT-5.1-Codex-Max	$1.25	$10	$3.44	400K
GPT-5.2	$1.75	$14	$4.81	400K
GPT-5.2 Pro	$21	$168	$57.75	400K

All OpenAI API prices