How long will your experiment take?

How many eligible visits do you have per day?

This is the number of people visiting your site that could see the change on a given day.

What percentage of visits will see the change?

What is your current conversion rate?

This is the percentage of your eligible visitors that currently complete your goal (e.g. purchasing or signing up).

How will you change conversion?

This is the percent by which you predict you will change your base conversion rate. Use the minimum that would be worth the effort, or play with different values.

How confident do you want to be of this?

If you are 95% confident in a result, this implies that with 5% probability the observed difference is in fact due to chance.

How likely should you be to detect the change?