Model Cost Profile

OpenAI: GPT-5.1-Codex

Developer: openai

Pricing updated Mar 11, 2026

Input rank: #263Output rank: #295

Live Pricing

Input: $1.25

Output: $10.00

Get API Key View full pricing leaderboard

Pricing via OpenRouter API · Last synced Mar 11, 2026 · MMLU score via public benchmark data

OpenAI's GPT-5.1-Codex model supports a substantial context window of 400,000 tokens, making it ideal for complex coding tasks, large document processing, and interactive applications that require extensive context retention. Teams leveraging this API can expect input costs of $1.25 per million tokens and output costs of $10.00 per million tokens, which necessitates careful budget planning for projects involving high-volume text generation. This model is particularly useful for software development, automated documentation, and real-time code assistance, providing a versatile tool for developers and businesses aiming to enhance productivity and innovation.

👁 Vision🔧 Tool Calling📋 Structured Output🧠 Reasoning

Context Window

400,000

Tokens

Input Price / 1M

$1.25

Prompt tokens

Output Price / 1M

$10.00

Completion tokens

Intelligence (MMLU)

86.0

Massive Multitask Language Understanding

Benchmark Scores

Standardized evaluation scores for OpenAI: GPT-5.1-Codex.

Benchmark	Score	Rank	Source
GPQA	86.0	#4 of 118	artificial_analysis
MMLU	86.0	#8 of 121	artificial_analysis

Side-by-Side Pricing Table

Usage Type	Price / 1M Tokens
Input (Prompt)	$1.25
Output (Completion)	$10.00

Compare with OpenAI: GPT-5 Compare with Deep Cogito: Cogito v2.1 671B Compare with Google: Gemini 2.5 Pro

Price History

OpenAI: GPT-5.1-Codex Pricing Trend

Input / 1M tokens0.0%Output / 1M tokens0.0%

Mar 7 — Mar 11

Current Input / 1M

$1.25

Current Output / 1M

$10.00

Cost Calculator

Estimate monthly spend for OpenAI: GPT-5.1-Codex based on your workload.

Input tokens / month

01.0B

Output tokens / month

0500M

Estimated Monthly Cost

$151

25M input + 12M output tokens

Same Workload on Other Models

Arcee AI: Trinity Large Preview (free)$0.00−$151 Arcee AI: Trinity Mini (free)$0.00−$151 Google: Gemma 3 12B (free)$0.00−$151 Google: Gemma 3 27B (free)$0.00−$151

Cheaper Alternatives to Compare

Quick links for cost-down decisions before production rollout.

OpenAI: GPT-5.1-Codex vs Arcee AI: Trinity Large Preview (free)OpenAI: GPT-5.1-Codex vs Arcee AI: Trinity Mini (free)OpenAI: GPT-5.1-Codex vs Google: Gemma 3 12B (free)OpenAI: GPT-5.1-Codex vs Google: Gemma 3 27B (free)

FAQ

Common pricing and benchmark questions for OpenAI: GPT-5.1-Codex.

How much does OpenAI: GPT-5.1-Codex cost per 1M input tokens?

OpenAI: GPT-5.1-Codex input pricing is $1.25 per 1M tokens based on the latest synced provider data.

How much does OpenAI: GPT-5.1-Codex cost per 1M output tokens?

OpenAI: GPT-5.1-Codex output pricing is $10.00 per 1M tokens based on the latest synced provider data.

What context window does OpenAI: GPT-5.1-Codex support?

OpenAI: GPT-5.1-Codex supports a context window of 400,000 tokens.

How can I compare OpenAI: GPT-5.1-Codex with cheaper alternatives?

Use the comparison links on this page to open direct model-vs-model pricing and benchmark pages, then evaluate monthly spend projections for your workload.