I am trying to get a formula to work that will subtract a start time from an ending time to produce how much time has elapsed in minutes. Here is the event code that I have come up with, that I think should work, but of course it doesn't and I don't know where I have gone wrong. Anyone that can give me direction, I would be most grateful.
$start = strtotime("recoveryStart");
$end = strtotime("recoveryFinish");
$values ["recoveryTotal"] = round(abs($end - $start) / 60,2). " minutes";