$dt = Carbon::create(2012, 4, 30, 0);
echo $dt->diffInDays($dt->copy()->addMonth());       // 30
echo $dt->diffInDays($dt->copy()->addWeek());       // 7
echo $dt->diffInMinutes($dt->copy()->addSeconds(59));   // 0
echo $dt->diffInMinutes($dt->copy()->addSeconds(60));   // 1