How cycle prediction works (and why it's sometimes off)
Cycle prediction is an estimate: it looks at the history you've logged and projects when your next period is likely to come. Because the body responds to stress, sleep and life changes, that date can shift — which is why the prediction is sometimes off. And, importantly: cycle prediction is not a contraceptive method.
The prediction learns from your history
The prediction works by looking at the cycles you've already logged: when each period started and how long it lasted. From that, the app calculates an average and projects the most likely next date. The more months logged, the closer the estimate tends to be to your reality. At the start, with little data, the prediction is more generic — it adjusts as you keep logging.
- It uses your own records, not an average from other people.
- More months of history make the estimate more tuned to you.
- At first, with little data, the prediction is naturally more approximate.
Why the date shifts: life interferes
The cycle is not a clock: it responds to what's happening in your life. Stress, poorly slept nights, travel across time zones, changes in routine, intense physical activity or shifts in weight can bring your period earlier or later. That's why even a prediction based on good history may not match the exact day. This is not an error of your body or of the app — it's the cycle being what it is: alive and sensitive to context. When this happens often, it's worth logging to see if there's a pattern.
An estimate is not contraception
This is the most important point: cycle prediction, including any estimate of more or less fertile days, is not meant to prevent pregnancy. Ovulation can happen on different days than predicted, and the estimate doesn't track that in real time. For contraception, the path is to talk with a health professional about the methods suited to you. Use prediction to organize yourself and know yourself better — never as a method to prevent or seek pregnancy without guidance.
- The prediction does not replace a contraceptive method in any situation.
- Ovulation can vary and the estimate does not track it in real time.
- To prevent or plan a pregnancy, talk with a health professional.
The prediction is a good guess based on you — not a promise, and never a contraceptive method.
A prediction that improves as you log
Nuya uses your history to estimate your next period and makes clear it's an estimate, not a guarantee. The more you log, the more the prediction adjusts to your rhythm — and the app is clear that this is not a contraceptive method. Your health in your hands, with honesty.
Download on the App StoreThis content is educational and does not replace evaluation by a health professional. Cycle prediction is an estimate and should not be used as a contraceptive method; for contraception or pregnancy planning, seek professional guidance.