Safe Period Calculator / Ovulation Calculator

The Safe Period Calculator helps women accurately calculate ovulation, safe period, and menstrual period based on their cycle.

How to Use

1. Enter the date of your last period.
2. Enter your average cycle length (usually 28 days).
3. Click "Calculate" to get the dates for ovulation, safe period, and menstrual period.

Principle

• Ovulation usually occurs about 14 days before the next period.
• The safe period is divided into pre-ovulation and post-ovulation safe periods.
• The calculator automatically estimates each phase based on your input.

Formula

• Ovulation period = About 14 days before next period.
• Pre-ovulation safe period = End of menstruation to start of ovulation.
• Post-ovulation safe period = End of ovulation to start of next period.

This tool is for reference only and not medical advice.