To use most period calculators, simply enter the date of your last menstrual period, how long your periods typically last and the length of your cycle, as evidenced by the period calculator created by Kotex. The calculat... More »

To predict when your next period will arrive, track your menstrual cycle using a paper calendar, smartphone or online calculator, notes Mayo Clinic. Tracking menstrual cycles helps women learn about the regularity of the... More »

A woman's period starts between 21 and 35 days from the first day of her last period, notes the Office on Women's Health. For teens, the cycle may be 21 to 45 days from the first day of their last period. The average men... More »

The most common reason for having two periods in one month is when a woman has a short cycle and one period occurs at the beginning of the month, and then about 24 days later, another occurs at the end of the month, acco... More »

Using a pregnancy test calculator is easy and simply requires inputting individual data including the date of the woman's last period as well as the typical length of the menstrual cycle, reports WebMD and BabyMed. Pregn... More »

To predict when your next period will arrive, track your menstrual cycle using a paper calendar, smartphone or online calculator, notes Mayo Clinic. Tracking menstrual cycles helps women learn about the regularity of the... More »

A woman can use a calendar to track her menstrual cycle by marking or circling each date of her period on the calendar, starting from the first day of the period, explains GirlsHealth.gov. She can count her full cycle fr... More »