---
title: duration
framework: foundation
role: symbol
role_heading: Instance Property
path: foundation/dateinterval/duration
---

# duration

The duration.

## Declaration

```swift
var duration: TimeInterval { get set }
```

## Discussion

Discussion Precondition: duration >= 0

## See Also

### Accessing Start Date, End Date, and Duration

- [start](foundation/dateinterval/start.md)
- [end](foundation/dateinterval/end.md)