Form has many calculations, slowing down input.

I'm using Adobe to create a workbook. The workbook has lots of forms for clients to fill out that complete calculations and auto-fill other fields within the document. The problem is that with so many fields being calculated, user input is slow. Once you enter a field the system calculated before moving to the next field. It's probably only two or three seconds to calc, but this is too long for someone who is working on the sheet.

I can't turn off calculations becuase it populates other parts of the workbook. I can't break the workbook down into smaller workbooks, this would defeat the purpose...

Any assistance appreciated!