Level 4 · The marketing mix as % of each column

A total answers “how much”. Many questions are about shares instead: what part of the spend went to social, and did that part grow? Excel’s PivotTable can show any value as a percentage of a total without a single extra formula.

Show values as

The sheet holds three channels’ daily spend from November 11 to 30, 2025, with a period column that splits it into the 13 days before Thanksgiving week (Nov 11-23) and the week itself (Nov 24-30). Build the table in two moves:

1. Rows channel, Columns period, Values amount summarised by Sum. That gives dollars.
2. Change Show values as to % of Column Total.

In Excel the second move is a right-click on any value → Show Values As → % of Column Total (or Value Field Settings → Show Values As).

Three kinds of percentage

Show values as	Each cell divided by	Adds up to 100%
% of Grand Total	the overall total	the whole table
% of Column Total	its column’s total	each column
% of Row Total	its row’s total	each row

The question decides which one. “Did the mix change from one period to the next?” compares columns, so every column must add up to 100%: % of Column Total.

What the table says

Sum of amount   period
channel       Nov 11-23    Nov 24-30    Grand Total
email            7.37%        6.84%         7.11%
paid            69.18%       66.58%        67.87%
social          23.45%       26.57%        25.02%
Grand Total    100.00%      100.00%       100.00%

Paid ads still take two thirds of the money, but in Thanksgiving week social rose by about three points and paid fell by about two and a half. In dollars, the week cost 27,436.12, slightly more than the 13 days before it (27,058.34): daily spend almost doubled. Both facts belong in Jordan’s answer.

Common mistakes

• Comparing raw sums across periods of different length. Shares or daily averages make them comparable; totals don’t.
• The wrong denominator. % of Grand Total here would make each period’s shares add up to its share of all spend (about 50% each), which hides the mix.
• Typing percentages next to the pivot. If someone refreshes the pivot with more days, typed shares go stale. Let the pivot compute them.
• Reading the Grand Total column as an average. It is each channel’s share of the whole 20 days, weighted by spend.