Call below function like : [self toStringFromDateTime:[NSDate date]]; - (NSString*)toStringFromDateTime:(NSDate*)datetime { // Purpose: Return a string of the specified date-time in UTC (Zulu) time zone in ISO 8601 format. // Example: 2013-10-25T06:59:43.431Z NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init]; //ISO DateFormatter [dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@" UTC "]]; [dateFormatter setDateFormat:@" yyyy-MM-dd'T'HH:mm:SS.SSS'Z' "]; NSString* dateTimeInIsoFormatForZuluTimeZone = [dateFormatter stringFromDate:datetime]; return dateTimeInIsoFormatForZuluTimeZone; }