Email open rate formula
Open rate is the share of delivered emails that were opened. Mailchimp describes it as the percentage of successfully delivered emails that recipients opened, measured with a tiny transparent image whose download counts as an open; it also counts a click as an open even if the image did not load.[1] Divide by delivered emails, not sent, so bounces do not drag the rate down.
- Delivered9,800
- Open rate39.8%
- Click rate3.16%
- Click-to-open rate7.9%
- Open rate without machine opens24.49%
Click-to-open rate (CTOR)
Click-to-open rate divides unique clicks by unique opens: of the people who opened, how many clicked. Click rate divides the same clicks by everyone delivered; Mailchimp defines it as the share of delivered emails that registered at least one click.[1] CTOR judges the content of the email, open rate judges the sender and subject line, and click rate is the product of the two.
| Open rate | 5% CTOR | 10% CTOR | 15% CTOR |
|---|---|---|---|
| 20% | 1% | 2% | 3% |
| 30% | 1.5% | 3% | 4.5% |
| 40% | 2% | 4% | 6% |
| 50% | 2.5% | 5% | 7.5% |
To value those clicks, carry them into the conversion rate calculator and then the cost per lead calculator if the email’s goal is a form fill. In Google Analytics, a sign-up or purchase that follows is counted as a key event you choose.[3]
Apple Mail Privacy Protection and open rates
Apple’s Mail Privacy Protection hides the reader’s IP address and prevents senders from seeing whether a message was opened.[2] In practice the tracking image is fetched for the reader, so opens are recorded that a person may never have made; Mailchimp warns that MPP and other bot activity can inflate open and click metrics.[1] If your platform reports machine opens, enter them to see the open rate without them, and lean on clicks and CTOR for decisions.
Email metric mistakes
- Dividing by emails sent. Bounces were never delivered; use delivered in the denominator.
- Using total opens. One reader opening five times is one unique open. Rates use unique counts.
- Trusting opens alone. Machine opens inflate the rate. Compare clicks and CTOR across sends.
Not affiliated with Mailchimp, Intuit or Apple. Platform names are trademarks of their owners and appear only to identify whose documentation we cite.
Frequently asked questions
How do you calculate email open rate?
Unique opens ÷ delivered emails × 100, where delivered = sent − bounces. 3,900 ÷ 9,800 × 100 = 39.8%.
What is click-to-open rate?
Unique clicks ÷ unique opens × 100: of the people who opened, the share who clicked. 310 ÷ 3,900 = 7.9%.
Why is my email open rate so high?
Apple Mail Privacy Protection and security scanners load the tracking image automatically, recording opens no person made. Remove machine opens or judge by clicks.
What is the difference between click rate and CTOR?
Click rate divides clicks by all delivered emails; CTOR divides them by opens only.