---
title: constant
framework: appkit
role: symbol
role_heading: Instance Property
path: appkit/nslayoutconstraint/constant
---

# constant

The constant added to the multiplied second attribute participating in the constraint.

## Declaration

```swift
var constant: CGFloat { get set }
```

## Discussion

Discussion Unlike the other properties, the constant can be modified after constraint creation. Setting the constant on an existing constraint performs much better than removing the constraint and adding a new one that’s exactly like the old except that it has a different constant.

## See Also

### Accessing constraint data

- [firstItem](appkit/nslayoutconstraint/firstitem.md)
- [firstAttribute](appkit/nslayoutconstraint/firstattribute.md)
- [relation](appkit/nslayoutconstraint/relation-swift.property.md)
- [secondItem](appkit/nslayoutconstraint/seconditem.md)
- [secondAttribute](appkit/nslayoutconstraint/secondattribute.md)
- [multiplier](appkit/nslayoutconstraint/multiplier.md)
- [firstAnchor](appkit/nslayoutconstraint/firstanchor.md)
- [secondAnchor](appkit/nslayoutconstraint/secondanchor.md)