Why the assumptions are editable
Renovation prices vary dramatically by country, city, property condition, finish quality, labor availability, and what is hidden behind the walls. This calculator therefore does the budgeting arithmetic while leaving the important local prices under your control.
Use a range, not one number
Enter a realistic low and high local rate. The result keeps uncertainty visible and adds a contingency on top, which is more useful for early planning than a falsely precise single estimate.