function doDate($nInterval) {
$dDate = new DateTime();
$dDate->modify(“$nInterval”);
return $dDate->format(‘Y-m-d H:i:s’);
}

echo doDate(‘+4 days’);
echo “\n”;
echo doDate(‘-5 hours’);
echo “\n”;
echo doDate(‘+2 weeks’);
echo “\n”;
echo doDate(‘-5 weeks -2 days’);

See how much more power it gives you? No messy 86400 stuff to add in, and it handles years, months, weeks, days, hours, minutes, and seconds, going backwards and forwards.

Note I could have also used your preferred formatting format for the .format() call of: ’l, F j, Y’.

The only trouble would be — and you only see this when you turn on a Strict Standards error mode in your pages — is that you should set the date and time first somewhere in your code to a particular timezone so that it doesn’t just guess your server time. This is done easily, however, like so, and should be called before running doDate(). It only needs to be called once and then all subsequent doDate() calls will work fine.

// change to your timezone or use “UTC” for Universal Coordinated Time if that’s your thing.
date_default_timezone_set(‘America/New_York’);

(I do PHP for a living, working from home.)

function doDate($days){
echo date(‘l, F j, Y’, time() + 86400 * $days);
}

Then you can pass it a positive (future) or negative (past) number.

I would also consider returning the date instead of echoing it out. Perhaps a showDate() function should be created which echos the result of the doDate function. This way, the doDate function could be reused if you ever needed to store the result in a variable, for example.