How do I figure out the length of my menstruation cycle?

How do I measure it? Is it the last day of my last period to the first day of my next one? First day to first day? First day to last day? I need help!How do I figure out the length of my menstruation cycle?
go to mymonthlycycles.com. it will give you a calculation of your cycle if you just fill in the information. it even has a calendar to help keep track of your cycle and period.How do I figure out the length of my menstruation cycle?
first to first or last to last, either way same answer i would think..........
Your menstrual cycle begins with the first day your period starts and ends the day before your next period starts. The average menstrual cycle lasts 28 days, though yours may be longer or shorter than that.

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