Delivery Rate is important in email marketing because it shows how many emails actually reach recipients’ inboxes. A high delivery rate means your list is clean, your sender reputation is strong, and your messages have a real chance to be opened, clicked, and converted. Without good deliverability, your entire email campaign fails before it even starts.
The formula for calculating email Delivery Rate is:

For example, you send 5,000 emails in a campaign. Out of those, 4,800 emails were successfully delivered (they didn’t bounce). So, your Delivery Rate should be 96%, meaning 96% of your emails reached recipients’ inboxes successfully as shown in the calculation below:

This 96% is considered a good Delivery Rate for email campaigns.