# Metering and charging logic (Flex Plan)

> When using UiPath® Document Understanding<sup>TM</sup> modern projects, it's essential to understand the consumption of AI units.

When using UiPath® Document Understanding<sup>TM</sup> modern projects, it's essential to understand the consumption of AI units.

:::tip
* For licensing information for classic projects, check the [Metering and charging logic](https://docs.uipath.com/document-understanding/automation-cloud/latest/classic-user-guide/metering-charging-logic) page from the Document Understanding User Guide for classic projects.
* To track your AI units consumption at organization and tenant level, check the [AI units consumption overview](https://docs.uipath.com/document-understanding/automation-cloud/latest/user-guide/ai-units-consumption-overview#%5Bpreview%5D-ai-units-consumption-overview) dashboard pages.
* To track AI units consumption for Document Understanding and AI Center projects, check the [IxP AI Unit consumption dashboard](https://docs.uipath.com/document-understanding/automation-cloud/latest/user-guide/document-understanding-ai-units-consumption#ixp-ai-unit-consumption-dashboard) page.
:::

## How charging works for modern projects

For Document Understanding modern projects, **only one single AI unit** is charged per page, regardless of the operations performed at runtime or the number of modern projects extracting data from the same page. The single per-page charge covers:

- Digitization, including OCR
- Extraction
- Classification

This applies to both robotic process automation (RPA) and REST API operations. For full REST API pricing — including how classic-project API calls are charged — see [Metering and Charging](https://docs.uipath.com/document-understanding/automation-cloud/latest/api-guide/metering-and-charging) in the API guide.

### Through Document Understanding activity packages

For both `DocumentUnderstanding.Activities` and `IntelligentOCR.Activities`, one AI unit is charged per page, regardless of the operations performed (digitization, extraction, or classification).

The one AI unit per-page rule applies only when:

- For `DocumentUnderstanding.Activities`: a pre-defined generative or modern project classifier or extractor is in use.
- For `IntelligentOCR.Activities`: a modern project classifier or extractor is in use.

If you use any other classifier or extractor, the respective consumption logic from classic projects is added to the one AI unit per page. For more information, see [Mixed projects](https://docs.uipath.com/document-understanding/automation-cloud/latest/user-guide/metering-and-charging-logic-unified-pricing#mixed-projects-modern--classic).

### Generative features — Activities 24.12-preview and above

This consumption applies in the following situations:

- Using activities version 24.12-preview and above with `PredefinedGenerative` projects.
- Using Document Understanding API v1.1 with `PredefinedGenerative` projects.

There are no additional AI units consumed when using Generative Classification and Generative Extraction. **Only one single AI unit** is charged per page, regardless of the operations performed, including Generative Classification and Generative Extraction.

:::note
Using **Generative Validation** consumes an additional **one AI unit** for each processed page. This brings the total to **two AI units** consumed per page when generative validation runs.
:::

### Generative features — Activities up to 24.12-preview

This consumption applies in the following situations:

- Using activities version up to 24.12-preview with the `Predefined` project.
- Using Document Understanding API v1.0 with the `Predefined` project.

In these versions, generative features incur specific charges per operation, as described in the following table.

Table 1. Generative features AI units consumption for activities versions up to 24.12-preview

| Generative feature | Consumed AI units |
| --- | --- |
| Generative Classifier | 0.2 per operation |
| Generative Extraction | 1.2 per operation |
| Generative Validation | 1 per operation |

## Model training

There are no AI units charged when training and serving models. You can train models freely to improve performance, develop new capabilities, and experiment without incurring additional AI units charges.

## Mixed projects (modern + classic)

When a project uses both classic and modern experiences, both pricing models apply based on their respective consumption.

The pricing model for classic projects applies in the following circumstances:

- Extraction and classification done using classic projects, regardless of the activity package used (`IntelligentOCR` or `DocumentUnderstanding.Activities`).
- Extraction and classification done using the out-of-the-box models included with the pre-defined project, regardless of the activity package used.
- REST API calls against classic-project models — classic per-capability rates apply, not the 1 AI unit per-page rule.

For full classic-project metering — including activity-based rates per OCR engine, classifier, and extractor — see the [Document Understanding User Guide for Classic Experience](https://docs.uipath.com/document-understanding/automation-cloud/latest/classic-user-guide/metering-charging-logic). For classic-project REST API rates specifically, see [Metering and Charging](https://docs.uipath.com/document-understanding/automation-cloud/latest/api-guide/metering-and-charging) in the API guide.