Date/Epoch Converter (JavaScript/PerlScript)

Current Date/Time: (JavaScript) !! Client-side JavaScript Unavailable !!

Current Date/Time: (PerlScript) !! Client-side PerlScript Unavailable !!

---

(enter new date or epoch below)
Win users: Conversion is automatically inserted into clipboard (CTRL-v to retrieve)

---

New Date

January February March April May June July August September October November December

: :

To Epoch

---

Convert Epoch To Date

To Date

What is Epoch

Epoch has a few meanings (see also http://dictionary.reference.com/search?q=epoch). The definition that we'll use is "0" in computer time. While there are folks who will argue this, for our purposes, this "0" time on our calendar was January 1, 1970 00:00:00 GMT. Epoch is useful in the programming world because it allows us to mathematically compare dates with other dates or some other measure of time.

Common Time Measures in Epoch

1 Millisecond = 1/1000 in Epoch (used frequently with JavaScript conversions)
1 Second = 1 in Epoch
1 Minute = 60 in Epoch
10 Minutes = 600 in Epoch
1 Hour = 3600 in Epoch
6 Hours = 21600 in Epoch
12 Hours = 43200 in Epoch
1 Day = 86400 in Epoch (24 Hours)
1 Week = 604800 in Epoch (7 Days / 168 Hours)
1 Month = (see below... number of days in the month)
 28 Days = 2419200 in Epoch (672 Hours)
 29 Days = 2505600 in Epoch (696 Hours)
 30 Days = 2592000 in Epoch (720 Hours)
 31 Days = 2678400 in Epoch (744 Hours)
 AVERAGE MONTHS IN YEAR = 2628000 in Epoch
  (365 / 12 = 30.416666666666666666666666666667) (average months)
  (30.416666666666666666666666666667 * 86400 = 2628000) (average months in Epoch)
1 Year = 31536000 in Epoch (365 days * 86400 seconds)

Examples of Usage

We wanted to turn messaging chunks on/off 3 days after a new signup for services.

1. First, we stored the epoch value of the date of each signup (for example, Jan 1, 2003 is 1041459471 in epoch). Now that the date value is an integer, we can do math with it.
2. Second, we calculate 3 days in epoch measures (seconds) as follows... (86400 * 3)
3. Third, compare the current time with the signup time, plus the 3 days epoch value.

By making signup date a variable, this rule can apply to anyone for whom we want to know 3 days into the future of their signup.
ex: $signup_date = 1041459471 (or whatever the epoch is for any given site) if ($current_time > ($signup_date + (86400 * 3))) then this site was signed up more than 3 days ago.