Glossary
Five-day challenge
Also called 5-day challenge.
Last reviewed 11 October 2026
What is a five-day challenge?
A five-day challenge is five daily emails that each ask the reader to do one small thing, usually framed by a pre-challenge email before day one and an offer on day six, which makes seven, so the unit of progress is an action rather than a lesson.
It differs from a course in what finishes it. A course is finished when the reader understands something; a challenge is finished when the reader has done something five times, which makes the writing the smaller half of the job.
The design problem is what you ask for on each of the five mornings, and whether an ordinary person with a job can actually do it before lunch. An action that takes an hour is a challenge with a completion rate of almost nothing, however good the email asking for it was.
See also
- Email course
An email course is a finite sequence of five to ten lessons delivered one email at a time, in order, on a clock that starts when each reader joins, and it ends on a day both of you knew about in advance.
- Evergreen and cohort courses
An evergreen course starts when each person confirms and is therefore running continuously, while a cohort course starts on one fixed date for everybody, so nobody in an evergreen course is ever late and nobody in a cohort is ever alone.
- Completion rate
A completion rate is the share of confirmed subscribers who reach the end of a course, and for a five-day course measured by a click on the last day it commonly runs between one in ten and one in four, with longer courses lower.
Read next
This term is covered properly in How to run a 5-day challenge by email, which is a longer piece on the subject.
Every other term is on the glossary index , the longer writing is in the guides, and what this site itself does is on the home page.
Thinking of writing an email course?
5dayemail hosts a five-to-ten day email course: you write it once, and everyone who joins your list gets one email a day, in order, starting from the day they confirm.
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