> For the complete documentation index, see [llms.txt](https://docs.userouter.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.userouter.ai/credits-and-billing/how-credits-work.md).

# How credits work

What a credit is worth, how every charge is calculated, and when credits come back.

## Units

| Unit          | Value                 |
| ------------- | --------------------- |
| 1 credit      | $0.001 of service     |
| 1,000 credits | 1 GEN = $1 of service |

* One balance covers chat, images and video.
* Balances and charges are always **whole credits**. Every charge is rounded **up** to the next whole credit, so the smallest possible charge is 1 credit.
* Your balance can never go below zero.

## How a charge is calculated

| Mode  | Billed by | Formula                                                                              |
| ----- | --------- | ------------------------------------------------------------------------------------ |
| Chat  | Tokens    | (input tokens × input rate + output tokens × output rate), rounded up once per reply |
| Image | Images    | price per image (rounded up) × number of images                                      |
| Video | Seconds   | rate per second × length, rounded up                                                 |

Rates are on the [Models](/get-started/models.md) page. See [Pricing](/get-started/pricing.md) for why they're lower than buying direct.

## The quote is binding

Before you submit, Studio shows:

* the price in credits and dollars,
* the official list price ("was"),
* the % off.

For images and video, the quote is exactly what you pay if the request succeeds. For chat, the quote covers the longest possible reply, and you pay only for what's used.

If your balance is below the quote, Studio won't submit the request.

## Reservations and settlement

{% stepper %}
{% step %}

### Reserve

When you submit, the quote is reserved from your balance. For chat, Router reserves enough for your message plus a **4,096-token** reply.
{% endstep %}

{% step %}

### Run

The model runs. The reserved credits show as spent while the request is running.
{% endstep %}

{% step %}

### Settle

* **Success:** images and video keep the quoted charge. Chat is charged for actual tokens, and the rest is refunded as *Unused reservation refund*.
* **Partial images:** you pay for delivered images only.
* **Failure or timeout:** the full reservation is refunded.
  {% endstep %}
  {% endstepper %}

Details: [Refunds and failed requests](/credits-and-billing/refunds.md).

## Credits are for service only

Credits pay for AI usage on Router. They can't be transferred to other accounts or turned back into GEN or cash.