Which fertility and period tracking apps can you trust?

Want to track your cycle? There are a lot of apps for that. But do they actually work? And are some better than others? We’ve written about period tracking and fertility awareness apps from a user perspective, but we’re happy to see the science community weighing in.

Two recent studies looking at the many free apps for period tracking and fertility awareness suggest that not all cycle tracking apps are created equal. Both studies focused only on free apps available in English; each used different measures to rate accuracy. Let’s take a closer look.

Period tracking apps

The main measure for accuracy in this study was whether the apps could handle something other than a 28-day menstrual cycle. (Regular cycles range from 21 to 35 days, and only a small minority of women have 28-day cycles, so apps designed only for 28-day cycles are going to leave lot of people out.) This study also dropped any apps that included misinformation.

Amazingly, only 20 apps made the cut based on those two criteria. Only two, Clue and Glow, scored well after looking at whether they were based on reputable research, had ads, or pushed in-app purchases.

Fertility awareness apps for contraception

The main measure for accuracy in this study was whether the apps correctly predicted what days would be within the fertile window. The researchers used data from real women to determine accuracy, and compared it to evidence-based estimates of the fertile window. Only 30 apps predicted the fertile window, and only four that are still on the market got it 100% correct. Those four were Sympto, iCycleBeads, LilyPro, and Lady Cycle.

Download with care

Both studies stressed that they could only offer a snapshot. It seems like there’s a new app every day, and newer ones may not have been included. (For example, we’ve got our eye on Spot On.) So check in with your health care provider if you have questions about tracking your cycle, and don’t believe everything you read in an app description.