---
title: MLBoundingBoxUnits
framework: createml
role: symbol
role_heading: Enumeration
path: createml/mlboundingboxunits
---

# MLBoundingBoxUnits

The units a bounding box annotation uses to define its position and size.

## Declaration

```swift
enum MLBoundingBoxUnits
```

## Overview

Overview All bounding box annotations in an annotation file must use the same units for their coordinates and size. See MLObjectDetector.AnnotationType.boundingBox(units:origin:anchor:).

## Topics

### Designating units

- [MLBoundingBoxUnits.pixel](createml/mlboundingboxunits/pixel.md)
- [MLBoundingBoxUnits.normalized](createml/mlboundingboxunits/normalized.md)

## Relationships

### Conforms To

- [Equatable](swift/equatable.md)
- [Escapable](swift/escapable.md)
- [Hashable](swift/hashable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Bounding box annotations

- [MLObjectDetector.AnnotationType.boundingBox(units:origin:anchor:)](createml/mlobjectdetector/annotationtype/boundingbox(units:origin:anchor:).md)
- [MLBoundingBoxAnchor](createml/mlboundingboxanchor.md)
- [MLBoundingBoxCoordinatesOrigin](createml/mlboundingboxcoordinatesorigin.md)