Your cycle. A look at the days ahead.
Explore your cycle phases, calculate the dates of your luteal phase or look at upcoming period starts. Choose a view and enter your values.
Your cycle takes shape here
Enter your last period start in the form. Your calculated date ranges will appear here.
This ring is only an example of a 28-day cycle.
Your inputs stay when you switch views. Opening a new page starts with empty inputs. Open this view on its own page
An orientation based on your inputs
The calculator repeats your cycle length. If your last period started further back, it shows the calculated cycle that contains today. It does not detect actual bleeding or phases. The results are not suitable for contraception, diagnosis or identifying ovulation.
Good to know
Which calculator fits my question?
Cycle phases shows the calculated breakdown of your current cycle. Luteal phase shows the start and end of the second part of the cycle using the duration you provide. Period calendar projects six period starts.
Which inputs do I need?
The period calendar needs your last period start and average cycle length. The phase views also need an assumed luteal phase length. You can change the default of 14 days.
What happens to my inputs?
The calculation runs in your browser. Your inputs are neither stored nor transmitted. They stay when you switch between the three views and are lost when you leave or reload the page.
Can I use this to find fertile days?
No. These calculators provide a timeline based on your inputs. They determine neither ovulation nor fertile days and are not suitable for contraception.
Follow your phases day by day in the BodySeasons app
In the app you record how you actually feel and recognise your own patterns across weeks and cycles. No points, no streaks, no grading.
Explore BodySeasons