Calculating start and end dates of a week.

A friend asked "How do I calculate start (monday) and end (sunday) dates from a given week number for a specified year?" Instead of having to come up with your own algorithm you can simply do the following in PHP 5.1 and higher:

// Monday
echo date(

// Sunday
echo date(

The format is " year 'W' weeknr ( daynr )?" where the default daynr is 1 being the Monday of that week. The daynr can be in the range 0 to 7. The weeknr is the ISO week number . Please note that the " year '-W' weeknr ( '-' daynr )?" format is only supported in PHP 5.2 and higher.


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Thanks Derek, that is going to make life a lot easier!

Keep it simple and just do strtotime('-1 Sunday',$currentDay);

it is simpler and uses less resources.

or you could use PEAR::Date(), it makes it very easy as well

@Ammar: Why would you want to use a wrapper class in PHP when the extension supports it?

Hey Dereck

thanks for confirming yet again why I love the Internet... I've been playing around with this particular problem for the last few days... any solution I had was not nearly as elegant and simple as this... glad I found this posting...will help tremendously.

echo date("Y-m-d", strtotime(date("Y").'W'.date('W')."7"));

If 1 for daynr represents monday, what does 0 represent? How can it accept values 0-7?

Thnx! Just what I was looking for!

Thank you very much!

Excellent example of exactly what a lot of people need. Please keep this example up for the rest of the PHP newbs like me!

You have just saved me a lot of time on deadline day at work.


Thank you very much. This threat was my first search result: "php calculate start end week"..

Wow. I had no clue about this. Thanks, man!

Very very usefull, I knew about the W weeks implemented in recent php but this is pretty useful, saved me on a thing I have to do at work :)


Exactly what I was looking for.

Even in 2013 this is very useful, thanks! Saved me much work

Thank you! I was getting very frustrated trying to get my dates to format properly, you're a lifesaver!

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