---
title: deltaY
framework: appkit
role: symbol
role_heading: Instance Property
path: appkit/nsevent/deltay
---

# deltaY

The y-coordinate change for scroll wheel, mouse-move, mouse-drag, and swipe events.

## Declaration

```swift
var deltaY: CGFloat { get }
```

## Discussion

Discussion This property is only valid for scroll wheel, mouse-move, mouse-drag, and swipe events. For swipe events, a nonzero value represents a horizontal swipe; -1.0 corresponds to swipe down and 1.0 corresponds to swipe up. For scroll wheel events, use scrollingDeltaY instead.

## See Also

### Getting scroll wheel and flick events

- [deltaX](appkit/nsevent/deltax.md)
- [deltaZ](appkit/nsevent/deltaz.md)
- [hasPreciseScrollingDeltas](appkit/nsevent/hasprecisescrollingdeltas.md)
- [scrollingDeltaX](appkit/nsevent/scrollingdeltax.md)
- [scrollingDeltaY](appkit/nsevent/scrollingdeltay.md)
- [momentumPhase](appkit/nsevent/momentumphase.md)
- [isDirectionInvertedFromDevice](appkit/nsevent/isdirectioninvertedfromdevice.md)