---
title: stiffness
framework: quartzcore
role: symbol
role_heading: Instance Property
path: quartzcore/caspringanimation/stiffness
---

# stiffness

The spring stiffness coefficient.

## Declaration

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

## Discussion

Discussion The default stiffness coefficient is 100. Increasing the stiffness reduces the number of oscillations and will reduce the settling duration. Decreasing the stiffness increases the the number of oscillations and will increase the settling duration.

## See Also

### Configuring Physical Attributes

- [damping](quartzcore/caspringanimation/damping.md)
- [initialVelocity](quartzcore/caspringanimation/initialvelocity.md)
- [mass](quartzcore/caspringanimation/mass.md)
- [settlingDuration](quartzcore/caspringanimation/settlingduration.md)