# Controlled Number

_How to add and configure a Controlled Number field in the {{Notebook}}
Editor._

---

## What This Field Does

A Controlled Number field accepts bounded numeric values, enforcing
minimum and maximum constraints at the point of entry. Use it for
ratings, scores, percentages, and measurements with known valid
ranges — such as pH (0–14), condition ratings (1–5), or percentage
cover (0–100). Unlike Number Input, it catches out-of-range entries
immediately rather than during post-processing.

## Adding the Field

To add this field, open the
[ADD A FIELD dialog](../shared-settings/adding-a-field.md), navigate to the
**NUMBERS** tab, and click the **Controlled Number** card. Then click
the **ADD FIELD** button in the lower right.

```{screenshot} field-types-design/controlled-number-01-add-field.png
:alt: Adding a Controlled Number — the NUMBERS tab in the ADD A FIELD dialog
:align: right
:width: 100%
```

## Configuring the Field

Click the field's **grey header bar** to expand it and see its settings.
For an overview of the settings shared by all fields — including Label,
Helper Text, Field ID, and the field toolbar — see
[Field Identity](../shared-settings/field-identity.md) and
[Field Toolbar](../shared-settings/field-toolbar.md).

Give the field a meaningful Label, review the auto-populated
Field ID, and add any desired Helper Text.

```{screenshot} field-types-design/controlled-number-02-configured.png
:alt: Controlled Number configuration in the {{Notebook}} Editor
:align: right
:width: 100%
```

### Controlled Number-Specific Settings

Below the identity fields, the Controlled Number provides settings for
defining the valid numeric range:

| Setting | What It Does                                                |
| ------- | ----------------------------------------------------------- |
| **Min** | The minimum allowed value. Entries below this are rejected. |
| **Max** | The maximum allowed value. Entries above this are rejected. |

### Shared Field Options

Configure any of the shared field options as needed.

For settings shared across all field types — including Required,
Annotation, Uncertainty, Conditions, Copy value to new records,
and Display in child records — see
[Field Options](../shared-settings/field-options.md).

## Tips

- **Set ranges based on what is physically plausible, not just what
  you expect.** For example, a depth field might use 0–500 cm rather
  than the 0–300 cm range you anticipate. Overly tight bounds block
  legitimate data entry and frustrate users in the field.
- **The field always has a numeric value** — it defaults to 0 and
  cannot store null (empty). If your workflow needs to distinguish
  "not measured" from "measured as zero", use Number Input instead.
- **Catches errors at the point of collection.** Out-of-range values
  (e.g., pH above 14, negative depths) are rejected immediately
  rather than slipping through to post-processing.
- **Enable Annotation and Uncertainty** for measurement fields where
  collectors might need to note the instrument type, recording
  conditions, estimation method, or unexpected out-of-range values.