The share that a subset of values makes up of a larger set, as a fraction. Written for GROUPBY and PIVOTBY, where it turns a sum into a percent-of-total column.

Syntax

=PERCENTOF(data_subset, data_all)

Example

=GROUPBY(A2:A50,C2:C50,PERCENTOF)

• Simple share

  =PERCENTOF({20,30},{20,30,50}) → 0.5

  50 out of 100.

• Share by group

  =GROUPBY(A2:A20,C2:C20,PERCENTOF) → Region | share

  Each region's share of total sales, adding to 100%.

• Share of a block

  =PERCENTOF(C2:C5,C2:C20) → 0.25

  The first four rows are a quarter of the column.

• Format the result as a percentage.
• In GROUPBY it replaces the SUM(group)/SUM(all) helper column.
• Requires Microsoft 365.

• #NAME? in Excel versions before 2024.
• Text in either range is ignored, which can make shares not add to 100%.