A period tracker that shows the whole cycle
Tap once when your period starts. Add flow, cramps or a bad-mood day if you want. After a few months you can see how long your cycles really run, and when your next period is likely.
A cycle runs from the first day of one period to the day before the next. The NHS gives 28 days as the average and calls 21 to 40 days common.
Logging the first day of each period is enough to see your own pattern. Her Good Days turns those dates into cycle lengths and an estimated next period, shown as a range of days.
What you can log
In the app, a woman with regular cycles usually sees these five in her Log menu, and can pin or hide any of them:
| Log item | What it records |
|---|---|
| Period | Start and end days |
| Flow or spotting | Light, medium or heavy, and spotting between periods |
| Cramps and PMS | Cramps, bloating, headaches, tender breasts, and how strong |
| Mood | One tap, any time of day |
| Sleep | Bedtime, wake time and how rested you feel |
Water, weight, meals and a journal sit under More.
How the next-period estimate works
The app averages your recent cycle lengths and counts forward from your last period. When your cycles vary, the estimate becomes a wider window, and the app says so. Reviewers of other trackers often complain that predictions miss irregular cycles, so we show the range instead of a single confident date.
Is my cycle normal?
The app does not judge your cycle. It shows the numbers, and a doctor is the right person to read them. The NHS suggests seeing a GP if your periods suddenly change, are very heavy, last longer than 7 days, or stop when you are not pregnant. Severe pain that stops you doing everyday things is also worth an appointment.
The doctor report lists your period dates, cycle lengths and logged symptoms on a few pages.
Your cycle changes with you
First periods
Teen mode for ages 13 to 17 keeps the cycle, mood and sleep tools.
Teen mode
Cycles getting longer or shorter
In your 40s, the same log starts to show perimenopause changes.
Perimenopause
Everything else you track
Sleep, food, water and habits sit in the same app.
What you can track
Other life stages
The features for this stage
Questions
How long is a normal menstrual cycle?
The NHS says the average cycle is 28 days, and that anything from 21 to 40 days is common. Yours can also vary from month to month.
Can I use the period predictions as birth control?
No. The app shows an estimated next period from your past cycles. It cannot tell you when pregnancy is unlikely, and it should never be used to prevent one.
Is the period tracker free?
Yes, with full history, charts and the doctor report. There is no premium tier and no trial.
What if my periods are irregular?
Keep logging the first day of each period. The estimate widens to a range when your cycles vary, and the cycle-length chart shows the spread, which is useful to bring to a doctor.
Start with today
Her Good Days is free, with no third-party ads and nothing to subscribe to. Free on iPhone and Android.