Some charting methods require you to mark your first fertile day (or last infertile day) by calculation. This can serve as a conservative buffer for opening the fertile window. It’s always used in combination with real-time observations of cervical fluid or cervix changes. Different methods have different ways of doing the calculation depending on your menstrual cycle / charting history. Please consult your chosen learning resource to know more!
- Open your data screen on the day when you'd like to mark your first fertile day by calc.
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- Double tap a day / column on your chart screen to edit that day's data
- Single tap a day on your calendar screen to edit that day's data
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- Scroll down to the 'Calculation' section of your data screen
- Tap to enable 'First fertile day by calc.'
Marking your first fertile day by calculation is relevant if you have the standard fertile window shading feature enabled in the app. The fertile window shading in the intimacy row of your chart screen will start on the day when your first fertile day by calculation or your point of change is marked - whichever comes first.