Counting Your Cycle Days and Length

When you want to determine how long your cycles are, you start counting from the first day of bleeding. You stop counting the day before your next period starts.

If you are not sure when exactly to start counting, use the first day you feel the need to use a tampon, pad or cup to prevent getting period blood on your clothes. Spotting is not really the start of your period. It is a sign your period is about to start.

The World Health Organization (WHO) considers cycle lengths between 21 and 35 days as normal/ Many doctors will treat cycle lengths up to 42 or 45 days as normal. The average cycle length is 28 days, although it is likely closer to 29 days than 28 days. It is generally better to have longer cycles than shorter cycles.

Cycles are considered regular if the longest and shortest cycles differ by 9 or fewer days.