Email Marketing Terms Explained
Glossary of key email marketing metrics and frequently asked questions.
Glossary of Key Terms
AOV (Average Order Value)
The average amount a customer spends each time they make a purchase. In email ROI calculations, this is multiplied by the number of conversions to estimate revenue.
Bounce Rate
The percentage of emails that were not delivered to recipients' inboxes. Hard bounces (invalid addresses) and soft bounces (temporary issues like full inbox) are tracked separately.
CTR (Click-Through Rate)
The percentage of email recipients who clicked on at least one link in your email. Calculated as (Unique Clicks / Emails Delivered) × 100. Industry average is 2.5%.
Conversion Rate
The percentage of clicks that result in a desired action (purchase, signup, download). Calculated as (Conversions / Unique Clicks) × 100. Industry average is 1.5%.
Deliverability
The percentage of emails that successfully reach recipients' inboxes (not spam folders). Industry average is 83%, but a well-maintained setup should achieve 93%+.
DMARC
Domain-based Message Authentication, Reporting & Conformance. An email authentication protocol that helps prevent email spoofing and improves deliverability.
ESP (Email Service Provider)
A company that offers email marketing services, including sending infrastructure, template design, automation, and analytics. Examples: Mailchimp, Klaviyo, Brevo.
List Decay
The natural rate at which email lists lose valid subscribers due to email address changes, job changes, or disengagement. Average rate is 22.5% per year (HubSpot).
List Hygiene
The practice of regularly cleaning your email list by removing invalid, unengaged, or risky addresses to maintain good deliverability and accurate metrics.
MPP (Mail Privacy Protection)
Apple's privacy feature that automatically loads remote content in the background, inflating open rates for Apple Mail users by an estimated 5-10%.
Open Rate
The percentage of delivered emails that were opened. Calculated as (Unique Opens / Emails Delivered) × 100. Cross-industry average is 22%.
ROI (Return on Investment)
In email marketing, ROI measures profitability as (Revenue - Total Cost) / Total Cost × 100. Average email marketing ROI is 3,600% ($36 per $1 spent).
Sender Reputation
A score ISPs assign to email senders based on sending volume, complaint rates, bounce rates, and engagement. A poor reputation leads to spam filtering.
SPF / DKIM
Email authentication protocols that verify your domain is authorized to send emails. Proper setup improves deliverability and prevents spoofing.
Frequently Asked Questions
What is email marketing ROI?
Email marketing ROI (Return on Investment) measures the profit you generate from email campaigns relative to what you spend. The formula is: (Revenue - Total Cost) / Total Cost × 100. The average email marketing ROI across all industries is 3,600%.
How is email revenue calculated?
Email revenue is calculated by multiplying: Monthly Volume × Deliverability Rate × Open Rate × CTR × Conversion Rate × Average Order Value. Each step in the funnel reduces the pool, so small improvements at the top compound significantly.
What is a good email open rate in 2026?
The cross-industry average open rate is 22%. Rates above 25% are considered good, and above 30% are excellent. Note that Apple's MPP may inflate reported open rates by 5-10%.
How much can I save by switching ESPs?
Savings vary by provider and subscriber count. For a 50,000-subscriber list, switching from Mailchimp ($59/mo) to Brevo ($25/mo) saves $408/year. Switching from ActiveCampaign ($229/mo at 50k) to ConvertKit ($119/mo) saves $1,320/year. Use our ROI calculator for your specific numbers.
What is the average deliverability rate?
The industry average deliverability rate is 83% (Campaign Monitor). However, a well-maintained email setup with proper authentication, good list hygiene, and a positive sender reputation should achieve 93-97% deliverability.
Is this calculator free to use?
Yes, the Open-rate.com Email Marketing ROI & Savings Calculator is completely free to use. No registration or login required. You can use it as many times as you want.