Safe Period Calculator
Estimate fertile window, ovulation, and safer days for regular or irregular cycles.
Cycle Mode
Typical range 21-35 days
Typical range 3-7 days
Typical range 12-16 days
Notes
This tool uses calendar-based estimation for reference only and is not contraception or medical advice. Consult a professional if needed.
Average Cycle Length (days)
28 days
Period Length (days)
5 days
Luteal Phase Length (days)
14 days
Cycle Prediction
Menstruation
2026-06-10 (Wed) - 2026-06-14 (Sun)
Next Period
2026-07-08 (Wed) - 2026-07-12 (Sun)
Fertile Window
2026-06-19 (Fri) - 2026-06-28 (Sun)
Ovulation
2026-06-24 (Wed)
Safer Days (Before Ovulation)
2026-06-15 (Mon) - 2026-06-18 (Thu)
Safer Days (After Ovulation)
2026-06-29 (Mon) - 2026-07-07 (Tue)
Calendar View
Click calendar date to set Last Period Start
Ovulation
Fertile
Safe Period
Menstruation
June 2026
S
M
T
W
T
F
S
July 2026
S
M
T
W
T
F
S
August 2026
S
M
T
W
T
F
S
Cycle Range Overview
Menstruation
Safer Days (Before Ovulation)
Fertile Window
Safer Days (After Ovulation)
About This Tool
This calculator offers a clean, visual cycle prediction experience. Enter last period start date, cycle length and period length to get ovulation, fertile window, safer days and next period range. For irregular cycles, use shortest/longest cycle mode to estimate a range. All processing stays in your browser for privacy.
Features
- 📆 Dual modes: Regular and irregular cycle estimation
- 🌼 Fertile window: Automatic fertile window and ovulation day
- 🩷 Safer days: Clear before/after safer day ranges
- 🗓️ Visual dates: See current and next cycle ranges
- 📋 Copy summary: One-click copy of predictions
- 🔒 Local processing: No data upload