---
title: "addTimeInterval(_:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/date/addtimeinterval(_:)"
---

# addTimeInterval(_:)

Adds a time interval to this date.

## Declaration

```swift
mutating func addTimeInterval(_ timeInterval: TimeInterval)
```

## Parameters

- `timeInterval`: The value to add, in seconds.

## Discussion

Discussion warning: This only adjusts an absolute value. If you wish to add calendrical concepts like hours, days, months then you must use a Calendar. That will take into account complexities like daylight saving time, months with different numbers of days, and more.

## See Also

### Adding or Subtracting a Time Interval

- [addingTimeInterval(_:)](foundation/date/addingtimeinterval(_:).md)
- [advanced(by:)](foundation/date/advanced(by:).md)
- [+(_:_:)](foundation/date/+(_:_:).md)
- [+=(_:_:)](foundation/date/+=(_:_:).md)
- [-(_:_:)](foundation/date/-(_:_:).md)
- [-=(_:_:)](foundation/date/-=(_:_:).md)