Menstrual Cycle Calculator: How Long Are My Cycles?

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Do you have a regular menstrual cycle? Knowing your menstrual cycle and having 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, and it typically lasts 3-5 days.

What is a menstrual cycle?

A menstrual cycle is the time between the first day of your menstrual period, the first day you bleed, until 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 regularity tool will calculate whether you have regular cycles, based on the dates of your last menstrual periods.

An estimated menstrual cycle period length can be calculated by following steps 1 through 3:

1. You need to determine the first day of your last menstrual period.

2. Know your menstrual cycle length. This is the number of days from the first day of your period until the last day before your next period.

3. Enter the date and menstrual cycle length, click the button and you'll calculate the next period(s).  

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.