Menstrual Cycle Calculator

In this code, the menstrual cycle calculator takes the date of the last period and the average cycle length as inputs. When the "Calculate" button is clicked, the calculateOvulation() function is called. This function retrieves the last period date and the cycle length, and calculates the estimated ovulation date by subtracting 14 days from the last period date and adding the cycle length.

The result is displayed in the "Ovulation Date" section.

Please note that this calculator provides an estimation of the ovulation date and may not be accurate for all individuals. It's always recommended to consult with a healthcare professional for precise tracking of your menstrual cycle and ovulation.


To calculate your menstrual cycle, you need to track the number of days between the first day of your period (cycle day 1) and the day before your next period starts. Here's how you can calculate your menstrual cycle:

Next Menses Date Calculator

Next Menses Date Calculator



Next Menses Date

  1. Start by tracking the first day of your period for at least 3 consecutive months. This will help you establish a pattern.
  2. Count the number of days between the first day of your period (cycle day 1) and the day before your next period starts (the day before cycle day 1 of your next period).
  3. Repeat this counting for each menstrual cycle you track.
  4. Once you have at least 3 recorded cycles, calculate the average number of days by adding up the total number of days for the cycles and dividing it by the number of cycles.

For example, let's say you have tracked your menstrual cycles for 3 months and the cycle lengths are as follows:

  • Month 1: 28 days
  • Month 2: 30 days
  • Month 3: 27 days

To calculate the average menstrual cycle length: (28 + 30 + 27) / 3 = 85 / 3 = 28.33 days

So, your average menstrual cycle length is approximately 28.33 days.

Please note that menstrual cycle lengths can vary from person to person and cycle to cycle. It's common to have slight variations in cycle length from month to month. Additionally, factors such as stress, illness, travel, and hormonal changes can affect the length of your menstrual cycle. By tracking your menstrual cycles over several months, you can get a better understanding of your individual cycle pattern. If you have concerns about your menstrual cycle, it's recommended to consult with a healthcare professional.