Menstrual Cycle Calculator

Do you have a regular menstrual cycle? Finding out whether you have regular menstrual cycles is vital for couples trying to conceive (TTC).

What is a menstrual period?

A menstrual period is the time when you bleed each month as the uterus sheds its lining, and it typically lasts 3-5 days, but can last slightly more or less.

What is a menstrual cycle?

A menstrual cycle is the time between the first day of your menstrual period (the first day you bleed) and the first day of the next menstrual period. The average menstrual cycle is 28 days long, although normal menstrual cycles can range anywhere from 21 to 35 days in adults, and from 21 to 45 days in young teens.

This menstrual cycle tool will calculate whether you have regular cycles, based on the dates of your last menstrual periods. 

How To Calculate Menstrual Cycles Length Manually

1. Get a calendar. This can be either a paper calendar or one on your computer, phone, or tablet.

2. Mark the FIRST day of your LAST period with an "X". This is day #1, the first day of your menstrual bleeding.

3. Count forward however many days your menstrual cycle normally is before you start. If you don't know, then just count 28 days.

4. Put your initials or some other identifying mark on the last day. This is when your period should start.