Find your fertile window, ovulation date, best days to conceive, and a full 3-month fertility calendar — all based on your cycle.
Your Cycle Details
Estimated Ovulation Day
—
—
🌸
Fertile Window Starts
—
5 days before ovulation
🌺
Fertile Window Ends
—
Day of ovulation
⭐
Best Day to Conceive
—
1–2 days before ovulation
📅
Next Period Expected
—
—
🔄
Current Cycle Phase
—
—
Where You Are in Your Cycle
Period
Follicular
Fertile
Ovulation
Luteal
S
M
T
W
T
F
S
PeriodFertileOvulationLuteal
Next 3 Cycles at a Glance
Related Tools
📅 Cycle History
Each calculation saves your cycle data so you can identify patterns and average cycle length over time.
No cycle history yet. Calculate to start tracking.
Frequently Asked Questions
How do I know when I'm ovulating?
Ovulation typically occurs 14 days before your next period. Signs include a slight rise in basal body temperature, clearer and stretchier cervical mucus (like raw egg white), and sometimes mild one-sided pelvic pain (Mittelschmerz). An ovulation predictor kit (OPK) detects the LH surge 24–36 hours before ovulation.
What is the fertile window?
The fertile window spans about 6 days — the 5 days before ovulation and the day of ovulation itself. Sperm can survive in the reproductive tract for up to 5 days, so having sex in the days leading up to ovulation gives the best chance of conception.
Can I get pregnant outside the fertile window?
It's very unlikely but not impossible. Ovulation timing can vary, and irregular cycles make prediction harder. If you're trying to conceive, tracking multiple cycles gives a more accurate picture of your personal pattern.
What if my cycle is irregular?
Irregular cycles (varying by more than a few days month to month) make calendar-based prediction less reliable. Track basal body temperature or use ovulation predictor kits to identify your actual ovulation day. Apps that use multiple fertility signals are more accurate for irregular cycles.
How accurate is this ovulation calculator?
The calculator gives a reliable estimate based on average cycle patterns. Actual ovulation can vary by several days even in regular cycles. For the best accuracy, combine calendar tracking with physical signs or OPK testing.