GPT-5.1-Codex
$1.25 per 1M input tokens and $10.00 per 1M output tokens · 400K context · vision, tools, reasoning, JSON.
Prices checked Oct 21, 2026 · tracked by LLM Cost Index since Oct 21, 2026
What GPT-5.1-Codex costs per month
Estimated monthly bill for typical workloads, using the cached-input price for repeated context. Try your own numbers in the cost calculator.
| Workload | Per month |
|---|---|
| Customer chatbot 1,000 conversations a day, 8 turns each | $1,048 |
| Document Q&A (RAG) 500 questions a day over retrieved documents | $177 |
| Coding / tool-using agent 200 tasks a day, long tool-heavy contexts | $388 |
| Content generation 30 long articles a day | $25.88 |
| Classification / extraction 100,000 short items a day | $1,575 |
Price history
We started tracking GPT-5.1-Codex on Oct 21, 2026; the chart appears as soon as there is a second data point. See all recent price changes.
Cheaper alternatives to GPT-5.1-Codex
Models with the same tool calling, image input, structured output for at least 20% less (3:1 input/output mix), most capable first.
| Model | Input / 1M | Output / 1M | Context | Capabilities |
|---|---|---|---|---|
| Muse Spark 1.3 Meta | $1.25 | $4.25 | 1.05M | visiontoolsreasoningJSON |
| MiMo-V2.6-Pro Xiaomi | $0.435 | $0.87 | 1.05M | visionaudiotoolsreasoningJSONopen weights |
| Step 5 Preview Stepfun | $1.00 | $2.70 | 1.05M | visiontoolsreasoningJSONopen weights |
| Claude Haiku 5.5 Anthropic | $0.10 | $0.50 | 1M | visiontoolsreasoningJSON |
| GLM 5.3 Flash Z.ai | $0.041 | $0.12 | 1.05M | visiontoolsreasoningJSONopen weights |
How to pay less for GPT-5.1-Codex
For a customer chatbot (1,000 conversations a day, 8 turns each) that costs $1,290 a month at list price without caching:
| Option | Per month | You save |
|---|---|---|
| Move to Muse Spark 1.3 (similar capabilities) | $569 | $721 (56%) |
| Use prompt caching (60% of input cached) | $1,048 | $242 (19%) |
Other workloads: cut-your-bill tool for GPT-5.1-Codex.
Specifications
| Model ID | openai/gpt-5.1-codex |
| Input | text, image |
| Output | text |
| Tool calling | Yes |
| Structured output | Yes |
| Reasoning mode | Yes |
| Open weights | No |
| Released | Nov 13, 2025 |
| Web search | $0.01 per request |
FAQ
- How much does GPT-5.1-Codex cost?
- $1.25 per million input tokens and $10.00 per million output tokens; cached input costs $0.13 per million. Prices as of Oct 21, 2026.
- What is the context window of GPT-5.1-Codex?
- 400K tokens, with up to 128K output tokens per response.
- Does GPT-5.1-Codex support images, tools and structured output?
- Images as input: yes. Tool calling: yes. Structured (JSON) output: yes. Reasoning mode: yes.
- What are cheaper alternatives to GPT-5.1-Codex?
- Models with the same key capabilities for at least 20% less include Muse Spark 1.3 ($1.25 / $4.25), MiMo-V2.6-Pro ($0.435 / $0.87), Step 5 Preview ($1.00 / $2.70).
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