Period Calculator
Use this calculator to estimate the future period days or the most probable ovulation days. Tracking your menstrual cycle can help with family planning and understanding your body's patterns.
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Modify the values and click the Calculate button to use
Result
Period Days
Ovulation Day
Fertile Window
| # | Period Start | Period End | Approx. Ovulation | Fertile Window |
|---|
Note: Ovulation is estimated at 14 days before the start of the next period. The fertile window spans approximately 5 days before ovulation through 1 day after. These are estimates based on average cycle data. Individual cycles may vary. This tool is for informational purposes only and should not replace professional medical advice.