How to convert NSDate to milliseconds in Objective-C?

Question

For example: assume NSDate tempdate = "05-23-2013". I want this value to be converted into milliseconds.

How can I do this with Objective-C?

What code have you tried so far? – jordanhill123 Apr 05 '13 at 06:55 — jordanhill123, Apr 05 '13 at 06:55

score 29 · Accepted Answer · edited May 23 '17 at 11:54

29

There is a similar post here and here.

Basically you have get the second form the reference date (1 January 2001, GMT) and multiply it with 1000.

NSTimeInterval seconds = [NSDate timeIntervalSinceReferenceDate];
double milliseconds = seconds*1000;

Cheers!

edited May 23 '17 at 11:54

Community

answered Apr 05 '13 at 07:03

alexcristea

6

`timeIntervalSinceReferenceDate` returns a `double`. If you assign that to an integer before multiplying by 1000, then you loose the milliseconds precision! – Martin R Apr 05 '13 at 07:15
Yes, sorry my bad. NSTimeInterval is a typedef of double: `typedef double NSTimeInterval;` – alexcristea Apr 05 '13 at 07:19
You actually need to use a double to store milliseconds, or you are likely to run into an overflow problem. double milliseconds = seconds*1000; – Michael Feb 04 '14 at 22:38

score 1 · Answer 2 · edited May 23 '17 at 12:34

The timeIntervalSince1970 will return seconds from 1970. There are other timeIntervalSince methods if needed.

For reverse conversion, I mean to say from milliseconds to NSDate, refer this stackoverflow article. Convert milliseconds to NSDate

Hope it ll solve your issue.

2 Answers2