# Recalculate a Calculated Field

When you set up a new calculated field, we only perform the calculation when we receive new event data that matches your calculation criteria. Recalculation is an optional way of running the calculation on historical event data. Recalculating historical data will update your participants’ profiles, but it won’t trigger your program rules to run — so you can safely perform a recalculation without affecting your program.

#### Start a recalculation

You can request a recalculation when setting up or editing a calculated field that uses either a `sum` or a `count` calculation.

1. From the left navigation menu, select ![](https://impact-1.gitbook.io/docs/emvxfLrwrlacc4y3y02Y/~gitbook/image?url=https%3A%2F%2F4048883401-files.gitbook.io%2F%7E%2Ffiles%2Fv0%2Fb%2Fgitbook-x-prod.appspot.com%2Fo%2Fspaces%252FwMLlMoFBtKJa8ptd3zaw%252Fuploads%252Fgit-blob-230534471fef5f40808e921e41ee44e4a06ded03%252Fe6cb9548999afdc1ed3ce4942e4cb5b45b5cecbd323267aac2a7cd1915fccc09.svg%3Falt%3Dmedia\&width=300\&dpr=3\&quality=100\&sign=71dd50ef\&sv=2) **\[Engage] → Data Sources → Fields**.
2. Open the field creation interface.
   * To create a new calculated field, select **Create Calculated Field**.
   * To edit an existing calculated field, locate it in the *Fields* table. Hover your cursor over the field and select **Edit**.
3. In the *Review* section, select the ![](https://4048883401-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwMLlMoFBtKJa8ptd3zaw%2Fuploads%2Fgit-blob-b5e1740618ed6571d97b8fed7c25a7678f85d375%2F299632fb6f4f91fbf9847471754cc6180e4284a65b4960af4c4ea472a159f552.svg?alt=media) **Recalculate values on save** checkbox.
4. Select **Save**.

{% hint style="info" %}
**Recalculation example:** It’s currently September 26th. You are setting up a calculated field with a fixed 1-month [tracking window](https://help.impact.com/brand/what-would-you-like-to-learn-about/advocate-program/manage-advocate-participants/custom-and-calculated-fields/tracking-windows-for-calculated-fields-explained). Rather than having your field start calculating values only from the 26th to the end of the month, you want it to take into account values from all of September. You can achieve this by selecting the ![](https://4048883401-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwMLlMoFBtKJa8ptd3zaw%2Fuploads%2Fgit-blob-b5e1740618ed6571d97b8fed7c25a7678f85d375%2F299632fb6f4f91fbf9847471754cc6180e4284a65b4960af4c4ea472a159f552.svg?alt=media) **\[Unchecked box]** **Backfill calculation** checkbox while setting up the field. The recalculation begins after you save your changes.
{% endhint %}

#### Processing order

{% hint style="info" %}
**Order of processing events:** Events may be processed out of order during a recalculation. This happens only if we receive new event data while the queued events are processing.
{% endhint %}

Recalculation is not instant and can take some time to complete, depending on how much data needs to be processed. You can check the status of your recalculation from the ![](https://impact-1.gitbook.io/docs/emvxfLrwrlacc4y3y02Y/~gitbook/image?url=https%3A%2F%2F4048883401-files.gitbook.io%2F%7E%2Ffiles%2Fv0%2Fb%2Fgitbook-x-prod.appspot.com%2Fo%2Fspaces%252FwMLlMoFBtKJa8ptd3zaw%252Fuploads%252Fgit-blob-230534471fef5f40808e921e41ee44e4a06ded03%252Fe6cb9548999afdc1ed3ce4942e4cb5b45b5cecbd323267aac2a7cd1915fccc09.svg%3Falt%3Dmedia\&width=300\&dpr=3\&quality=100\&sign=71dd50ef\&sv=2) **\[Engage] → Data Sources → Processes page**.

Any events that we receive while your recalculation is in progress will be placed in a queue until the recalculation is done. After the recalculation is completed, we will start to process the events in the order they were received.