DAX code
% of Parent Category =
VAR CurrentSales = [Total Sales]
VAR CategoryTotal = CALCULATE([Total Sales], ALLEXCEPT('Product', 'Product'[Category]))
RETURN
DIVIDE(CurrentSales, CategoryTotal)
Shows each product's sales as a percentage of its own category's total, not the grand total.
Type your table and column names once. Every measure below updates.
% of Parent Category =
VAR CurrentSales = [Total Sales]
VAR CategoryTotal = CALCULATE([Total Sales], ALLEXCEPT('Product', 'Product'[Category]))
RETURN
DIVIDE(CurrentSales, CategoryTotal)
Replace 'Product'[Category] with whatever column represents the "parent" level in your hierarchy.
Browse all 175 measures in the Power BI DAX Measures Library, or search the library for something similar to % of Parent Category.