Discrepancy with the summary row in Looker Studio

If you've noticed discrepancies in the summary row of your Looker Studio table, you're not alone. This difference stems from how Looker Studio processes calculated formulas, leading to results that might not align with your expectations.

Why does the Summary Row differ?

Looker Studio employs a unique approach to handling calculated metrics in tables. While individual rows use your custom formula at a granular level, the summary row works differently—it recalculates the formula using aggregated totals. This behavior can cause the summary row value to diverge from the sum of individual row results.

Let's review it with an example:

We have created the calculated field labeled "Example" with the formula:
total cost / reach * 1000

Here’s how Looker Studio processes it:

1. Row-Level Calculation:
   The formula is applied to each row, using the specific values of total cost and reach for that row. For instance:

   • Row 1: 4563,3 / 539.336 * 1000 = 8,46
   • Row 2: 2401,95 / 221.467 * 1000 = 10,85

2. Summary Row Calculation:
   Instead of summing the calculated values from individual rows (e.g., 8,46 + 10,85 = 19,31), Looker Studio recalculates the formula using the aggregated totals of total cost and reach across all rows:

   • Aggregated totals: total cost = 6.965,25, reach = 760.803
   • Summary row formula: (6.965,25 / 760.803) * 1000 = 9,19

   As a result, the summary row value (9,19) differs from the sum of individual row results (19,31).

The difference in the summary row of your Looker Studio table is not an error but a reflection of its calculation method. By recalculating metrics using aggregated totals, Looker Studio provides a summary that reflects a holistic application of the formula.

As always, please do not hesitate to contact us via our live chat on our website or via e-mail if you still have doubts or questions. We are happy to help!