How to Use Notion Rollup to Calculate Average of Related Page Property

You need to calculate the average of a number property from pages linked to a parent database in Notion. The Rollup property can pull a value from a related page and then apply a function like Average to it. This article explains how to set up the relation and rollup properties correctly to compute the average of a target number field. By the end, you will have a working average calculation that updates automatically as you add or change related pages.

What a Notion Rollup Does and Why You Need a Relation First

A Rollup property in Notion reads a property from a related page and can perform a calculation on it. The calculation options include Sum, Count, Average, Min, Max, and several text-based functions. To use Average, you must first have a Relation property that connects the parent database to a child database. The child database must contain a Number property with the values you want to average.

The Rollup property does not work on its own. It always depends on an existing Relation. When you configure the Rollup, you select which Relation to use, then which property from the related pages to read, and finally which calculation function to apply. The Average function adds up all the values from the related pages and divides by the count of those pages.

Prerequisites for the Average Rollup

You need two databases in your Notion workspace. The parent database holds the pages where the average result will appear. The child database holds the pages with the numeric values to average. Both databases must be connected through a Relation property created in the parent database. The child database must have at least one Number property. The values in that Number property must be numbers without currency symbols or text.

Steps to Create a Relation and Rollup for Average Calculation

1. Create the child database with a Number property
   Open Notion and create a new database. Name it something like “Scores” or “Expenses.” Add a Number property by clicking the + in the table header. Name the property “Value” or “Amount.” Enter numeric values in the rows of this database. Each row will later be linked to a parent page.
2. Create or open the parent database
   Create a new database or use an existing one. This database will contain the pages that need the average calculation. For example, a “Projects” database where each project has multiple expenses in the child database.
3. Add a Relation property to the parent database
   In the parent database, click the + button at the top of the table. Select Relation. In the dialog, choose the child database you created in step 1. Click Create Relation. A new column appears in both databases. In the parent table, each cell now shows a link to child pages. Click a cell to search and select the related child pages. For the average to work, link at least two child pages to one parent page.
4. Add a Rollup property to the parent database
   Click the + button again in the parent database. Select Rollup. A configuration panel opens. In the Relation field, choose the Relation property you just created. In the Property field, choose the Number property from the child database (for example, “Value”). In the Calculate field, click the dropdown and select Average. Click Save or press Enter. The Rollup column now displays the average of all linked child page values.
5. Test the average calculation
   Add a new child page and link it to the same parent page. The Rollup value updates automatically. Change a number in one of the linked child pages. The Rollup recalculates. Verify the result by manually adding the values and dividing by the count.

Things to Avoid When Using Rollup to Calculate Average

Rollup Shows No Value or Shows an Error

If the Rollup column is blank, check that the Relation property has at least one linked child page. If no child pages are linked, the Rollup has nothing to read. Also confirm that the child database property you selected is a Number type. Text properties with numbers written as words will not work.

Rollup Includes Empty or Zero Values in the Average

Notion Rollup treats empty Number properties as zero. If a linked child page has an empty number field, the Rollup counts it as zero and includes it in the average. To avoid this, ensure every linked child page has a numeric value entered. Alternatively, filter your linked pages to exclude rows with empty number fields.

Rollup Average Does Not Update When Child Values Change

The Rollup recalculates automatically when you edit a child page. If the Rollup does not update, refresh the page by reloading the browser or clicking away from the database and back. In the Notion desktop app, close and reopen the workspace. If the issue persists, check that the Relation is still intact and not accidentally deleted.

Rollup Shows Different Results Than Manual Calculation

Double-check that you selected the correct Relation and the correct child property. If you have multiple Relation properties, the Rollup might be reading from the wrong one. Also verify that the child pages linked to the parent are the ones you intend to include. Remove any child pages that should not be part of the average.

Notion Rollup Average vs Manual Formula Average

Item	Rollup Average	Manual Formula Average
Setup time	Requires a Relation property first	No relation needed, uses a formula property with sum and count
Data source	Reads from linked child pages in a separate database	Reads from properties within the same database
Automatic updates	Updates when child pages change	Updates when any referenced property in the same row changes
Flexibility	Can average values across many linked pages	Cannot average across related pages without a Rollup
Error handling	Treats empty values as zero	Can use conditional logic to skip empty values

You can now set up a Rollup property to calculate the average of a number property from related pages in Notion. Start by creating the child database with a Number property, then add a Relation in the parent database, and finally configure the Rollup with the Average function. For advanced use, combine the Rollup with a Formula property to round the result or format it as currency.