GPT-5.6 Luna API pricing
GPT-5.6 Luna costs $0.20 per million input tokens and $1.20 per million output tokens on OpenAI's API. Input read back from the prompt cache costs $0.02 per million. A typical support chat reply (1,500 tokens in, 300 out) costs about $0.00066.
| Input | $0.20 per 1M tokens |
|---|---|
| Output | $1.20 per 1M tokens |
| Cached input | $0.02 per 1M tokens |
| Cache writes | $0.25 per 1M tokens |
| Long prompts | $0.40 in, $1.80 out per 1M tokens above the prompt size OpenAI sets for this model |
| Context window | 1.05M tokens |
| Reads | files, images, text |
| Released | July 9, 2026 |
What requests cost on GPT-5.6 Luna
The same four requests on every page, so you can compare models directly.
| Request | Tokens in / out | Per request | Per 10,000 requests |
|---|---|---|---|
| A support chat reply | 1,500 / 300 | $0.00066 | $6.60 |
| Summarizing a 10-page document | 6,000 / 500 | $0.0018 | $18.00 |
| Sorting a support ticket into a category | 400 / 5 | $0.000086 | $0.86 |
| A question about a 120-page document | 60,000 / 800 | $0.013 | $130 |
OpenAI's cheapest model here, GPT-5 nano, costs 70% less for the same chat reply. Whether it is good enough depends on the request: simple ones (sorting, short summaries, extraction) often are, hard reasoning often isn't.
Other OpenAI models
| Model | Input | Output | A chat reply | Next to GPT-5.6 Luna |
|---|---|---|---|---|
| GPT-5 nano | $0.05 | $0.40 | $0.00019 | 70% less |
| GPT-4.1 nano | $0.10 | $0.40 | $0.00027 | 59% less |
| GPT-6 Luna | $0.10 | $0.50 | $0.00030 | 55% less |
| GPT-4o mini | $0.15 | $0.60 | $0.00040 | 39% less |
| GPT-5.4 nano | $0.20 | $1.25 | $0.00068 | 2% more |
| GPT-5 mini | $0.25 | $2 | $0.00097 | 48% more |
| GPT-4.1 mini | $0.40 | $1.60 | $0.0011 | 64% more |
| GPT-5.4 mini | $0.75 | $4.50 | $0.0025 | 3.8x the price |
| o4-mini | $1.10 | $4.40 | $0.0030 | 4.5x the price |
| o3-mini | $1.10 | $4.40 | $0.0030 | 4.5x the price |
| GPT-5.1 | $1.25 | $10 | $0.0049 | 7.4x the price |
| GPT-5 | $1.25 | $10 | $0.0049 | 7.4x the price |
| GPT-4.1 | $2 | $8 | $0.0054 | 8.2x the price |
| o3 | $2 | $8 | $0.0054 | 8.2x the price |
| GPT-6.1 Sol | $2 | $10 | $0.0060 | 9.1x the price |
| GPT-6 Sol | $2 | $10 | $0.0060 | 9.1x the price |
| GPT-5.6 Terra | $2 | $12 | $0.0066 | 10x the price |
| GPT-4o | $2.50 | $10 | $0.0067 | 10x the price |
| GPT-5.2 | $1.75 | $14 | $0.0068 | 10x the price |
| GPT-5.4 | $2.50 | $15 | $0.0083 | 13x the price |
| GPT-5.6 Sol | $4 | $20 | $0.012 | 18x the price |
| GPT-5.5 | $5 | $30 | $0.017 | 25x the price |
| GPT-6 Astra | $10 | $50 | $0.03 | 45x the price |
| o1 | $15 | $60 | $0.041 | 61x the price |
| o3-pro | $20 | $80 | $0.054 | 82x the price |
| GPT-5 Pro | $15 | $120 | $0.059 | 89x the price |
| GPT-5.2 Pro | $21 | $168 | $0.082 | 124x the price |
| GPT-5.5 Pro | $30 | $180 | $0.099 | 150x the price |
| GPT-5.4 Pro | $30 | $180 | $0.099 | 150x the price |
| o1-pro | $150 | $600 | $0.405 | 614x the price |
Similar price from other companies
| Model | Input | Output | A chat reply | Next to GPT-5.6 Luna |
|---|---|---|---|---|
| Gemini 3.1 Flash-Lite | $0.25 | $1.50 | $0.00082 | 25% more |
| Gemini 3.5 Flash-Lite | $0.30 | $2.50 | $0.0012 | 82% more |
| Gemini 2.5 Flash | $0.30 | $2.50 | $0.0012 | 82% more |
Paying GPT-5.6 Luna prices for every request?
Most apps send simple requests to the same strong model as the hard ones. PromptUnit checks each request your app sends and uses a cheaper model only when it is just as good for that request. You pay 20% of what it saves, and nothing if it saves nothing.
Checked October 14, 2026. Prices are read every day from OpenAI's pricing page. Context window, inputs and release date come from OpenRouter's public model list.
These are the standard list prices on each provider's own API. Batch, flex and priority tiers, cloud platforms such as Amazon Bedrock or Google Vertex AI, and regional endpoints are priced differently. Request costs above count input and output tokens only, not cache, search or image fees.