But if you have an irregular period, you'd need to take an ovulation test and input the results for a truly accurate reading.

The Xiaomi Smart Band 9 is one of the cheapest fitness trackers that's worth buying, despite some rough edges.

Outstanding functionality. Very easy instructions to sync it with smartphones. It counts steps, heart rate and sleep ...

The Oura Ring Membership, which is required if you want to unlock the ring’s full potential, costs $5.99; you get one month ...