Predict your next period and track your cycle — private, instant, free
This calculator predicts your next period based on a regular cycle length. The average cycle is 28 days, but normal cycles range from 21–35 days. Your fertile window is typically Days 10–17 of your cycle (around ovulation at Day 14 for a 28-day cycle).
This tool is for general tracking only. For medical advice, speak with your healthcare provider.