Find your per-day salary and the deduction for unpaid leave days using the divisor your employer follows.
It depends on your company policy. Some divide by 30, some by the days in that month, some by 26 working days.
It is the salary cut for unpaid leave: the per-day salary multiplied by the days absent.
Yes. It works on the gross figure you enter.
No. Everything is worked out in your browser and nothing you type is sent to a server.