Email Click to Open Rate Calculator
What proportion of measured unique openers also clicked? Check the formula, a worked example and the stated measurement limits.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Unique clicking recipients (recipients) | Enter a whole count in recipients; keep the reporting population consistent. |
| Measured unique openers (recipients) | Enter a whole count in recipients; keep the reporting population consistent. |
Understanding your result
CTOR describes measured response among measured openers. It does not describe all delivered recipients and should not be substituted for delivered-based click rate.
Common mistakes
- Do not use total opens rather than unique openers.
- An inflated opener count can lower CTOR without any change in actual clicks.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Choose a consistent measurement basis
Both counts should refer to the same campaign. Use a reporting convention in which clicking recipients are included in the opener population, and apply consistent bot filtering.
A second independently worked case
Zero unique clickers among ten measured openers gives 0%. Inputs: Unique clicking recipients: 0 recipients; Measured unique openers: 10 recipients. Results: Click-to-open rate: 0 %.
Precision and output units
Displayed results: Click-to-open rate in %, rounded to 2 decimal places. Display rounding does not establish the precision of the original measurements or estimates. A small positive rate can round to 0.00%; inspect the underlying counts before treating displayed zero as an absence of events.
Calculation checks, sources and review limits
What proportion of measured unique openers also clicked?
What proportion of measured unique openers also clicked? Check the formula, a worked example and the stated measurement limits.
Common uses
- What proportion of measured unique openers also clicked
- Compare Email Click to Open Rate across scenarios under matching definitions.
How it works
Divide unique clicking recipients by measured unique openers. Compare this with delivered-based click rate to see how changing the denominator changes the interpretation.
Worked example
120 ÷ 1,000 × 100 = 12%. Enter unique clicking recipients 120 recipients, measured unique openers 1000 recipients. The independently worked result is click-to-open rate 12 %. Compare this example with your reporting definitions before substituting your own figures.
FAQ
Why can click rate and click-to-open rate differ substantially?
For 4,000 deliveries, 1,000 measured openers and 120 clickers, delivered-based click rate is 3%, while click-to-open rate is 12%. They answer different questions by using different denominators.
Can privacy-related opens affect CTOR?
Yes. Automated or privacy-related opens can enlarge the measured opener population without corresponding reader activity. CTOR is a ratio of the supplied tracking measurements, not an independent measure of attention.