How to calculate the date when booking accommodation

Travel

I'm going on an overseas trip this time, but I don't know how to calculate the date when I make a reservation. For example, if I stay for 2 nights and 3 days from 1 to 3, do I reserve for 3 days like 1, 2, 3 days?

Or do you make a reservation like this after calculating the date of sleep?

  581 6   7 years ago