Whatever you are doing requires you to understand how your display is laid out.
Access works in units called "Twips" which comes out as 1440 twips/inch. You need to determine how Access sees your calculator screen, whatever it is, to determine the number of twips it will hold. Then your main form would have the Form.Height and Form.Width adjusted to those dimensions.
BUT there is a huge question here. What does a calculator have to do with Access forms? Because you run a MASSIVE risk if any part of what you are trying to do involves a WiFi setup leading back to an Access database. That would be a database killer. Therefore, please clarify your intent.