Email Open Rate Calculator
Email open rate is the foundational engagement metric for email marketing campaigns. It tells you what fraction of your delivered emails were actually opened, giving you a signal of subject line effectiveness, sender trust, and list health. However, open rate alone is incomplete; the click-to-open rate (CTOR) shows whether the opened emails drove engagement through clicks. This calculator computes email open rate, click rate, CTOR, and unsubscribe rate from your campaign data. Enter the number of emails sent, bounced, unique opens, unique clicks, and unsubscribes to get a complete campaign performance summary.
Email metrics formulas
Delivered = Sent - Bounced
Open Rate = Unique Opens / Delivered * 100
Click Rate = Unique Clicks / Delivered * 100
CTOR = Unique Clicks / Unique Opens * 100
Unsubscribe Rate = Unsubscribes / Delivered * 100
Email marketing benchmarks
- Open rate: 15 to 25% for marketing email; 50%+ for transactional.
- Click rate: 2 to 5% is typical for marketing campaigns.
- CTOR: 10 to 20% indicates good content relevance.
- Unsubscribe rate above 0.5% per campaign signals list or content problems.
Email open rate: frequently asked questions
What is email open rate?
Email open rate is the percentage of delivered emails that are opened by recipients. It is calculated as unique opens divided by emails delivered (not sent, to exclude bounces), multiplied by 100.
What is a good email open rate?
Average email open rates vary by industry. Marketing emails typically see 15 to 25%. B2B email averages 20 to 30%. Transactional emails (receipts, confirmations) often exceed 50%. Benchmarks from the U.S. Direct Mail Association and industry surveys provide segment-specific data.
What is click-to-open rate (CTOR)?
CTOR is the percentage of openers who also clicked a link. It is calculated as unique clicks divided by unique opens. CTOR measures content relevance and CTA effectiveness among those who opened.
How does Apple Mail Privacy Protection affect open rates?
Apple MPP, introduced in iOS 15, prefetches email content and triggers open pixels for Apple Mail users regardless of whether they actually read the email. This inflates open rate metrics for lists with many Apple Mail users.
How do I improve email open rate?
Test subject line length (under 50 characters performs best), personalize the subject line with the recipient's name or company, optimize send time, maintain list hygiene by removing inactive subscribers, and improve sender reputation through authentication (SPF, DKIM, DMARC).
Sources
- U.S. Federal Trade Commission - CAN-SPAM Act: CAN-SPAM Compliance Guide.
- U.S. Federal Trade Commission: Email Unsubscribe Requirements.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.