Period Calculator
Track your menstrual cycle and calculate ovulation, fertility windows, and next period dates based on your last period and cycle length.
Your Menstrual Cycle Forecast
| Next Period Start | - |
|---|---|
| Next Period End | - |
| Ovulation Date | - |
| Fertile Window | - |
| Pregnancy Test Day | - |
About the Period Calculator
The Period Calculator estimates key dates in your menstrual cycle based on the first day of your last period and your average cycle length. Understanding your cycle can help with family planning, tracking fertility, or simply being prepared for your next period.
How the Calculator Works
The calculator uses the following calculations:
- Next Period: Your next period is estimated by adding your average cycle length to the first day of your last period.
- Ovulation: Ovulation typically occurs about 14 days before your next period starts (for a 28-day cycle).
- Fertile Window: The 5-6 days leading up to and including ovulation when pregnancy is most likely.
- Pregnancy Test Day: The earliest day you might get a positive pregnancy test if conception occurred during ovulation.
Understanding Your Cycle
A menstrual cycle is counted from the first day of one period to the first day of the next. The average cycle is 28 days, but normal cycles can range from 21 to 35 days. The cycle has two main phases:
- Follicular Phase: From period start to ovulation (variable length)
- Luteal Phase: From ovulation to next period (typically 12-16 days)
Important Notes
This calculator provides estimates only. Many factors can affect your cycle, including stress, illness, travel, and hormonal changes. If your cycles are irregular or you have concerns about your menstrual health, consult a healthcare provider.