---
title: weight
framework: uikit
role: symbol
role_heading: Type Property
path: uikit/uifontdescriptor/traitkey/weight
---

# weight

The numerical value that corresponds to a font face.

## Declaration

```swift
static let weight: UIFontDescriptor.TraitKey
```

## Discussion

Discussion The value of this key is an NSNumber object. The valid value range is from -1.0 to 1.0, where 0.0 corresponds to the regular weight constant. The negative side of the value range indicates that the font is light or thin; the positive side means the font is heavier or bolder. For example, the font face ultraLight has the approximate value of -0.8, and black has the approximate value of 0.62. When providing a weight that doesn’t precisely match a font face in the family, the system locates an available face that represents the closest match. You can use a font face constant to specify a weight; for a list of constants, see UIFont.Weight. To access the weight of a font, first retrieve the font’s traits dictionary information: let font = UIFont.systemFont(ofSize: 21, weight: .bold) if let traits = font.fontDescriptor.object(forKey: .traits) as? [UIFontDescriptor.TraitKey: Any]{     let weightValue = traits[.weight] }

## See Also

### Font traits

- [slant](uikit/uifontdescriptor/traitkey/slant.md)
- [symbolic](uikit/uifontdescriptor/traitkey/symbolic.md)
- [width](uikit/uifontdescriptor/traitkey/width.md)