Frequently asked questions

Most menstrual cycles last between 21 and 35 days, counted from the first day of one period to the first day of the next, with 28 days as the average. Teenagers can have a wider range, from 21 to 45 days, in the first few years after their first period. A cycle outside these ranges most months is worth mentioning to a doctor.

A typical period lasts 2 to 7 days, with about 5 days being average and the heaviest flow usually in the first 1 to 3 days. A period that regularly runs longer than 7 days is worth discussing with a doctor.

Most girls in the U.S. and U.K. start their periods around age 12, though it is normal to start anywhere from age 8 upwards. If periods haven’t started by 15, or by 3 years after breast development begins, a doctor visit is a good idea.

Periods are generally considered irregular if your cycle length regularly falls outside 21 to 35 days, if the gap between periods varies by more than about 7 to 9 days from cycle to cycle, or if periods stop for 3 months or more without pregnancy. Irregular cycles have many possible causes, including stress, weight changes, thyroid conditions and PCOS.

Ovulation usually happens about 14 days before your next period starts. Pregnancy is possible from around 6 days before ovulation through the day of ovulation, with the two days before and the day of ovulation being the most fertile. Because ovulation timing shifts with cycle length, the fertile window moves too — which is why Cycella recalculates it from your own logged cycles rather than assuming a fixed day.

No. Fertility awareness methods require careful, consistent tracking (often combining cycle length, temperature and cervical mucus) and are less effective at preventing pregnancy than most other methods, especially with irregular cycles. Cycella’s predictions are estimates for awareness, not a contraception plan — talk to a doctor or health worker about proven birth control methods.

More than half of people who menstruate have some cramping pain for a day or two each cycle, usually caused by natural chemicals called prostaglandins. That kind of pain is normal and often eases with over-the-counter pain relief or a heat pad. Pain severe enough to stop your normal activities, that gets worse over time, or that comes with heavy bleeding, is worth checking with a doctor — it can have a treatable cause.

Polycystic ovary syndrome (PCOS) is a common hormonal condition that can cause irregular or missed periods, excess hair growth or acne, and can affect fertility and long-term metabolic health. It affects roughly 1 in 10 people of reproductive age. There is no single test for PCOS — diagnosis usually involves a doctor reviewing your cycle history, symptoms, and sometimes blood tests or an ultrasound.

PMS (premenstrual syndrome) is a group of physical and mood changes, like bloating, irritability or tiredness, that some people notice in the one to two weeks before a period. PMDD (premenstrual dysphoric disorder) is a more severe form that can seriously affect mood, relationships or daily life, and usually benefits from a doctor’s help. Logging mood alongside your cycle can make the pattern easier to describe at an appointment.

Consider a doctor visit if you soak through a pad or tampon every hour for several hours, your period lasts more than 7 days, your cycles are regularly shorter than 21 or longer than 35 days, you miss periods without being pregnant, or pain regularly stops you from your normal activities. Cycella can help you describe the pattern, but it doesn’t replace a medical opinion.

No. Cycella works fully without an account, and never asks for your name, email or phone number.

Cycella looks at the cycles you’ve logged and predicts your next period, ovulation and fertile window from your own pattern. The more cycles you log, and the more consistently, the more accurate the prediction gets. A single irregular cycle, or a missed log, won’t throw off the whole prediction.

Flow, mood, symptoms, notes and pad changes are all a few taps from the home screen. A quick daily log is enough to build a useful history — you don’t need to fill in every field every day.

Yes. Cycella can put together a summary of your recent cycles, symptoms and notes that you can show a doctor, which is often clearer than trying to recall a few months of history from memory.

Yes. Cycella launches completely free, with no paywalled features. If we introduce paid features later, we’ll always show the price and terms before you pay.

On your phone, by default. Nothing leaves your device unless you turn on backup or partner sharing, both of which are optional and off until you choose them.

Your data is encrypted on your phone with a 12-word key before it’s uploaded. Our server stores only the encrypted file — it can’t read it. If you lose your key and your phone, we can’t recover your data either, so keep your 12 words somewhere safe.

Only what you switch on: your mood, your next period date and your pad status. Your flow, symptoms, notes and any doctor report stay private to you and are never shared, even with sharing turned on.

No. There are no ads, no analytics and no trackers in Cycella, and we don’t sell, rent or trade data to anyone. See the full Privacy Policy for details.

Yes, at any time, from Me › Delete all my data. This clears your phone and deletes any backup or partner boxes from our server.

No. Cycella provides estimates based on what you log. It doesn’t diagnose, treat or prevent any condition, and it isn’t a substitute for seeing a doctor.

Talk to a doctor. Soaking through protection every hour for several hours, or pain that stops your normal activities, are both reasons to get checked rather than wait it out. In an emergency, go to a hospital or call your local emergency number.

No. Partner sharing is opt-in per item, and you can turn it off at any time. Nothing is shared by default.

Cycella can be used at any age. If you’re under 18, backup and partner sharing aren’t available, so nothing about you leaves your phone, and we recommend using Cycella with a parent or guardian’s knowledge.