Newsletter Metrics Calculator: Open, Click, Unsubscribe, Bounce and Complaint Rates

How to use it

• Copy the numbers for one send from your email service's report. Only "sent" is required; fill in whatever else you have.
• Use unique opens and clicks (each person counted once). Total opens or clicks will make the rates look higher.
• If you leave "delivered" blank, the calculator uses sent minus bounces.

What each metric means

• Delivery rate = delivered ÷ sent: the share of emails accepted by the recipient's mail server. Emails filtered into spam still count as delivered.
• Bounce rate = bounces ÷ sent: the share returned as undeliverable.
• Open rate = unique opens ÷ delivered: the share of people for whom a tiny tracking image loaded.
• Click rate = unique clicks ÷ delivered: the share of people who clicked a link.
• Click-to-open rate (CTOR) = unique clicks ÷ unique opens: the share of openers who clicked.
• Unsubscribe rate = unsubscribes ÷ delivered.
• Spam complaint rate = spam complaints ÷ delivered.

The thresholds behind the verdicts

None of these are legal limits. They're guidance published by mailbox providers and email services. Gmail and Yahoo calculate spam rates from their own data (Yahoo uses mail delivered to the inbox as the base), so their figures may not match this calculator. You can see your Gmail figure in Google Postmaster Tools.

• Spam complaint rate: under 0.3%, a requirement in both Gmail's and Yahoo's sender guidelines. Google also recommends staying under 0.1%.
• Bounce rate: under 2%, as Amazon SES recommends. At 5% or more, Amazon SES places an account under review.
• Unsubscribe rate: 0.5% or less per send is a commonly used guide. For reference, Mailchimp's all-industry average is 0.22%.
• Open and click rates: shown against published averages (opens about 25–35%, clicks about 1–3%) without a good-or-bad verdict, because they vary so much by industry and audience.

Treat open rates as approximate

An open is counted when a tiny image in the email loads. With Apple Mail Privacy Protection turned on, images load when the email arrives, so unread emails can count as opened. People who block images, on the other hand, can read without being counted. Comparing with your own past sends is more useful than comparing with other companies' averages.