Email Open Rate Calculator Formula

Understand the math behind the email open rate calculator. Each variable explained with a worked example.

Use the Email Open Rate Calculator

Formulas Used

Open Rate

open_rate = emails_delivered > 0 ? (emails_opened / emails_delivered) * 100 : 0

Emails Not Opened

unopened = emails_delivered - emails_opened

Variables

VariableDescriptionDefault
emails_openedEmails Opened800
emails_deliveredEmails Delivered4000

How It Works

How to Calculate Email Open Rate

Formula

Open Rate = (Emails Opened / Emails Delivered) x 100

Open rate indicates how well your subject lines and sender reputation attract attention in crowded inboxes. Use delivered emails (not sent emails) as the denominator to exclude bounces, which the recipient never had a chance to see. Note that privacy features like Apple Mail Privacy Protection can inflate open rates by pre-loading tracking pixels.

Worked Example

An email campaign delivered 4,000 emails and 800 were opened.

emails_opened = 800emails_delivered = 4000
  1. 01Open Rate = (800 / 4,000) x 100 = 20%
  2. 02Unopened = 4,000 - 800 = 3,200

Ready to run the numbers?

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