Predicted upcoming period dates, from your last period and average cycle length.
A prediction based on your average cycle length — actual cycles vary.
Each one adds another multiple of your average cycle length to the first day of your last period: next period = last period date + n × cycle length, for n = 1 through 6.
It's the number of days since the first day of your last period, counting that day as day 1. It tells you where you currently are in your cycle relative to your last tracked period.
The calculator assumes every cycle is exactly your entered average length, but real cycles vary month to month from stress, illness, travel and other factors — so treat these as estimates, not guarantees.