Email Marketing Open Rate, CTR & CTOR (Click-to-Open

Retention & Lifecycle Marketing: The Critical Distinction Between CTR and CTOR

While Open Rate measures subject line hook and sender trust, understanding link engagement requires separating CTR from CTOR:

• CTR (Click-Through Rate): Measures total clicks against the entire delivered audience). A lower open rate artificially depresses your CTR even if your email content is world-class.

• CTOR (Click-to-Open Rate): Isolates only the people who actually opened and read the email). CTOR is the ultimate metric for measuring the persuasive power of your email body copy, visual layout, and call-to-action (CTA) buttons.

• Revenue Per Email (RPE): The ultimate financial productivity metric for newsletter and e-commerce lifecycle managers; multiplying list size by RPE forecasts campaign cash flow.

How to Use This Calculator

Enter your Total Emails Sent (e.g. 25,000), Bounced Emails (Hard + Soft Bounces) (e.g. 350), Unique Email Opens (e.g. 6,150), Unique Link Clicks (e.g. 820), Unsubscribes / Opt-Outs (e.g. 45), and Total Attributed Campaign Revenue () (e.g. 9,400). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Email Marketing \& Campaign Performance equations:

Delivered Emails = Total Sent - Bounced Emails

Deliverability Rate (\%) = ((Delivered Emails) / (Total Sent)) × 100\%

Open Rate (OR \%) = ((Unique Opens) / (Delivered Emails)) × 100\%

Click-Through Rate (CTR \%) = ((Unique Clicks) / (Delivered Emails)) × 100\%

Click-to-Open Rate (CTOR \%) = ((Unique Clicks) / (Unique Opens)) × 100\%

Revenue Per Email Sent (RPE) = (Attributed Campaign Revenue) / (Total Emails Sent)

Worked Example

For example, sending an email campaign to 25,000 subscribers with 350 bounces (24,650 delivered, 98.60\% deliverability), 6,150 unique opens, 820 unique clicks, 45 unsubscribes, and \9,400.00 in attributed sales: The Open Rate is \. The Click-Through Rate is \. The Click-to-Open Rate (CTOR) is \ (reflecting strong content engagement). The campaign generates 0.376 Revenue Per Email Sent (0.381 per delivered email) with a low 0.18% unsubscribe rate.

Understanding Your Result

Marketing metrics are most useful as trends over time rather than isolated snapshots. Benchmark your result against your own historical performance first, then against industry averages. Attribution models (last-click vs. multi-touch) can produce dramatically different channel ROI figures — ensure consistent attribution methodology before making channel budget decisions. Statistical significance requires sufficient sample size: most A/B test decisions need a minimum of 1,000 conversions per variant for reliable results.