For what it's worth, Wirecutter recommends Clue (https://thewirecutter.com/reviews/best-free-menstrual-tracking-app/ https://thewirecutter.com/reviews/best-free

For what it's worth, Wirecutter recommends Clue (https://thewirecutter.com/reviews/best-free-menstrual-tracking-app/ https://thewirecutter.com/reviews/best-free-menstrual-tracki...), which has iOS (https://itunes.apple.com/us/app/id657189652 https://itunes.apple.com/us/app/id657189652) and Play Store (https://play.google.com/store/apps/details?id=com.clue.android https://play.google.com/store/apps/details?id=com.clue.andro...) versions.