Even though I don't take hormonal birth control, my period is like clockwork: every 29 days on the nose, with very occasional forays into 28-day or 30-day territory. I'm one of the lucky ones — plenty of women out there don't have regular menstrual cycles, for any number of reasons. 

Despite my regularity‚ before I used a period tracker app on my iPhone, I was often surprised when "Aunt Flo" came to visit. (My excuse is that time always seems to pass more quickly than I realize!) But no more — for the past couple years I've been using iPeriod, a smartphone app that gives me 7-day, 5-day, and then daily reminders that my period is coming, based on my cycle. For me, it's a genuine life improvement, especially when I'm planning a trip a couple months in advance — it can predict your next 12 cycles into the future — but most especially because now I'm never caught off-guard since I get ample reminders. 

I also have mittelschmerz — which means I can feel when I'm ovulating — and I use my app to record which side I'm dropping eggs from each month (I figure that might be useful to know if I ever have a health issue). It's also reassuring that the weird stretchy pain that accompanies ovulation is indeed that, which I can easily verify by looking at the monthly calendar on my app. It shows when I'm at that point in my cycle, as well as other important moments, in a quick-glance calendar feature. 

Period-tracking apps also end up keeping a detailed record of your cycles. Depending on how much information you load into them, you can also look at month-to-month changes in your cycle and what they are affected by. I determined, by tracking what I ate and when I exercised (and recorded the discomfort level of my cramps), that when I eat lots of veggies and work out vigorously every day for the week leading up to menstruation, pain during my period is almost nonexistent. I had suspected this, but having the hard data in front of me to compare month-to-month was motivating. It's also useful to have this detailed information immediately available when you're talking to a doctor about health issues. 

There are several well-reviewed tracking apps now available: 

iPeriod is the oldest period-tracking app, and my favorite (it's also free). As mentioned above, I love the at-a-glance monthly calendar, the alerts, and the relatively low-key visual for the app (if someone is using my phone, they wouldn't necessarily know what the app is by looking at its icon). I also like that you can keep very detailed information in the calendar by clicking on each day, which can be useful if you want to keep track of certain aspects of your cycle and compare them month over month.

Clue is a super-modern, beautifully designed period tracker that's "not pink" (that's part of the brand's tagline), which I appreciate. It's less complex and more graphic than iPeriod, but also has less room for notes and detailed period information. It does have a great calendar so you can see where you are quickly and easily, and it's also free. 

Period Tracker Lite is another free app that keeps track of all the usual details, but instead of a message, flowers appear on the screen when you are most fertile during the month, which is great if you are trying to conceive, but I would find annoying. 

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