---
title: timeIntervalSinceReferenceDate
framework: foundation
role: symbol
role_heading: Type Property
path: foundation/nsdate/timeintervalsincereferencedate-swift.type.property
---

# timeIntervalSinceReferenceDate

The interval between 00:00:00 UTC on 1 January 2001 and the current date and time.

## Declaration

```swift
class var timeIntervalSinceReferenceDate: TimeInterval { get }
```

## Return Value

Return Value The interval between the system’s absolute reference date (00:00:00 UTC on 1 January 2001) and the current date and time.

## Discussion

Discussion This method is the primitive method for NSDate. If you subclass NSDate, you must override this method with your own implementation for it.

## See Also

### Getting Time Intervals

- [timeIntervalSince(_:)](foundation/nsdate/timeintervalsince(_:).md)
- [timeIntervalSinceNow](foundation/nsdate/timeintervalsincenow.md)
- [timeIntervalSinceReferenceDate](foundation/nsdate/timeintervalsincereferencedate-swift.property.md)
- [timeIntervalSince1970](foundation/nsdate/timeintervalsince1970.md)
- [NSTimeIntervalSince1970](foundation/nstimeintervalsince1970.md)