---
title: birthRate
framework: quartzcore
role: symbol
role_heading: Instance Property
path: quartzcore/caemitterlayer/birthrate
---

# birthRate

Defines a multiplier that is applied to the cell-defined birth rate. Animatable

## Declaration

```swift
var birthRate: Float { get set }
```

## Discussion

Discussion The birth rate of each cell is multiplied by this number to give the actual number of particles created every second. Default value is 1.0.

## See Also

### Emitter Cell Attribute Multipliers

- [scale](quartzcore/caemitterlayer/scale.md)
- [seed](quartzcore/caemitterlayer/seed.md)
- [spin](quartzcore/caemitterlayer/spin.md)
- [velocity](quartzcore/caemitterlayer/velocity.md)
- [emitterMode](quartzcore/caemitterlayer/emittermode.md)
- [lifetime](quartzcore/caemitterlayer/lifetime.md)
- [preservesDepth](quartzcore/caemitterlayer/preservesdepth.md)