Did subject line B win, or was it chance?
Enter how many emails were delivered and how many were opened, clicked or led to an order. The calculator tells you whether the difference holds, and how big your next test has to be.
Variant B wins. The difference holds at 95% confidence, the click rate is 22.2% higher.
Difference B vs. A
+22.2%
p-value
0.022
Chance that B is better
98.9%
Range of the difference
+0.07 to +0.95
percentage points, at the chosen confidence level
Runs in your browser. No sign-up, we store nothing.
How it works
Three numbers per variant, one answer.
- 01
Pick the metric
Opens for subject line tests, clicks for content and layout, orders if your shop attributes them to the newsletter.
- 02
Enter the numbers
Delivered emails and results for A and B. You find them in the report of your email tool.
- 03
Read the verdict
If the difference reaches your confidence level, you have a winner. If not, the calculator shows how many recipients it would take to prove it.
Frequently asked questions
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