# Rollup Formulas - COUNT, SUM, AVG, MAX, MIN

Rollup formulas are very useful when you want to summarize data from related Apps.

The following connected Apps will be used as an example to explain each rollup type. For more information about Fields, click here.

 Projects App Tasks App Project Title Task Title Project Notes Responsible Stage Status Hours Budgeted Estimate (in hours) Deadline Time taken (in hours) Related Tasks Main Project

Rollups are only available on App relationships.

### COUNT

Using the COUNT rollup type, you can display the number of tasks related to any project, as shown below:

In this case, our Project has two related Tasks:

Therefore, the resulting value will be 2.

### SUM

The SUM rollup type works on all the Number Fields available in the connected Tasks App. We can use it to show the total time taken for all Tasks to be completed, as shown below:

Using the same Tasks from the COUNT example, this formula will add time taken in both Tasks (45 + 25)

You can combine rollups with other operations to gather more useful information. For example, we can check if the project has exceeded the budgeted hours.

In this case, the resulting value will be shown in a Tickbox Field.

### AVG

The AVG can be calculated by using the COUNT and SUM rollup types. For example, we can find out the average task duration using the following formula:

Since both the COUNT and SUM are dynamic, the average will change automatically each time you add more task or update task durations.

### MAX

When using the MAX rollup type on a Number Field, the formula will return the highest value from all related records. For example, we can find out the number of hours taken for the task with the longest duration, as shown below:

Looking back at the tasks for this project, we can see that the task 'Design new homepage template' has the longest duration.

Hence, that number (45) will be the result of the MAX rollup type.

### MIN

When using the MIN rollup type on a Number Field, the formula will return the smallest value from all related records. For example, we can find out the number of hours taken for the task with the shortest duration, as shown below:

Looking back at the tasks for this project, we can see that the task 'Finalize new Dashboard animation' has the shortest duration.

Hence, that number (25) will be the result of the MIN rollup type.

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