Period
Calculator
Predict upcoming menstrual periods, ovulation dates, and fertile windows based on cycle length and last period date.
Cycle Settings
days
days
Next Period
Sep 1, 2026
Current Cycle Day
Day 1
Legend
PeriodMenstruation days
OvulationEstimated ovulation
FertileFertile window
Predictions
| # | Period Start | Period End | Ovulation | Fertile Window |
|---|---|---|---|---|
| 1 | Sep 1, 2026 | Sep 5, 2026 | Sep 15, 2026 | Sep 10, 2026 – Sep 15, 2026 |
| 2 | Sep 29, 2026 | Oct 3, 2026 | Oct 13, 2026 | Oct 8, 2026 – Oct 13, 2026 |
| 3 | Oct 27, 2026 | Oct 31, 2026 | Nov 10, 2026 | Nov 5, 2026 – Nov 10, 2026 |
| 4 | Nov 24, 2026 | Nov 28, 2026 | Dec 8, 2026 | Dec 3, 2026 – Dec 8, 2026 |
| 5 | Dec 22, 2026 | Dec 26, 2026 | Jan 5, 2027 | Dec 31, 2026 – Jan 5, 2027 |
| 6 | Jan 19, 2027 | Jan 23, 2027 | Feb 2, 2027 | Jan 28, 2027 – Feb 2, 2027 |
Predictions
Cycle 1
Period
Sep 1, 2026 – Sep 5, 2026
Ovulation
Sep 15, 2026
Fertile Window
Sep 10, 2026 – Sep 15, 2026
Cycle 2
Period
Sep 29, 2026 – Oct 3, 2026
Ovulation
Oct 13, 2026
Fertile Window
Oct 8, 2026 – Oct 13, 2026
Cycle 3
Period
Oct 27, 2026 – Oct 31, 2026
Ovulation
Nov 10, 2026
Fertile Window
Nov 5, 2026 – Nov 10, 2026
Cycle 4
Period
Nov 24, 2026 – Nov 28, 2026
Ovulation
Dec 8, 2026
Fertile Window
Dec 3, 2026 – Dec 8, 2026
Cycle 5
Period
Dec 22, 2026 – Dec 26, 2026
Ovulation
Jan 5, 2027
Fertile Window
Dec 31, 2026 – Jan 5, 2027
Cycle 6
Period
Jan 19, 2027 – Jan 23, 2027
Ovulation
Feb 2, 2027
Fertile Window
Jan 28, 2027 – Feb 2, 2027