Zingtree has built a handy webhook where you can calculate the number of days between dates. You just need to add a new Webhook and install it into the node where you want the calculation to take place. Here's how to set it up:

Step 1: Add the Webhook to your Organization

1. Go to Account, My Apps.
2. Click on Add Webhook.
3. Give the Webhook a name (like "Number of days"), and enter this for the webhook URL:
   https://zingtree.com/apps/webhook/filters/date_difference.php?

 The end result looks like this: 

Step 2: Call the webhook from your tree

Open your tree, and edit the node where you want the age calculated.

1. Under the Apps / Webhooks tab, click Add App / Webhook.
2. Pick the Webhook you added previously ("Number of days" , for example).
3. In the Message Data area, enter something like this:
   date1={first date}&date2={second date}&var=diff
4. Save the changes to the node.
   
   

Your edits should look something like this:

Now just use #‌diff# anywhere you want to show the date difference.

• Webhooks Library
• Troubleshooting Webhooks