When to use this calculator
Find unique recorded opens as a share of delivered campaign emails. Automated privacy opens can affect measurement, so this is not a direct measure of human attention.
Explore the marketing & customer calculators for other questions in this topic. For a related calculation, use the Gross Revenue Retention Calculator: Measure recurring-revenue retention before expansion in the starting customer cohort.
PUTTING IT INTO PRACTICE
Email Open Rate: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Unique opening recipients (integer) | 400 |
| Delivered emails (integer) | 2,000 |
| Result | 20 % |
- Check the input labels and enter the example values above.
- Apply the relationship: Open rate (%) = unique openers/delivered emails × 100.
- The result is 20 %, rounded for display.
How to interpret your result
Automated privacy opens can affect measurement, so this is not a direct measure of human attention.
Define the event, audience and attribution window before calculating a rate. Clicks, customers and orders are different units. Acquisition cost and campaign CPA may cover different spending categories.
Frequently asked questions
Should I count unique users or total events?
Use the definition matching your metric. State it consistently because repeat events can produce a different rate from unique people.
When is the email open rate calculator useful?
Find unique recorded opens as a share of delivered campaign emails. Automated privacy opens can affect measurement, so this is not a direct measure of human attention.
How do I use the email open rate calculator?
Enter unique opening recipients (integer), delivered emails (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Open rate (%) = unique openers/delivered emails × 100.
What should I check before using the result?
Automated privacy opens can affect measurement, so this is not a direct measure of human attention.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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