Ovulation Calculator
Ovulation Window · Fertile Days · Cycle Calendar · 6-Month Planner
Your Cycle Details
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Luteal phase is the time from ovulation to your next period — typically 12–16 days. If unsure, use 14. A short luteal phase (<10 days) may affect implantation.

Estimated Ovulation Date
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Cycle Status
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Peak Fertile Days
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Highest conception probability — 2 days before + ovulation day
Full Fertile Window
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Sperm survive 5 days — intercourse any day in this window can lead to conception
Pregnancy Test Date
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Earliest reliable home pregnancy test (14 days after ovulation / missed period)
Next Period Expected
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Predicted start of next menstrual cycle based on your cycle length
Ovulation Day
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Cycle Day of Ovulation
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Fertile Window (days)
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Days Until Ovulation
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Follicular Phase
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Luteal Phase
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Next Period
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If Conceived → EDD
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Ovulation Insights
Earliest fertile day (sperm can survive to ovulation):—
Latest fertile day (egg survives ~24hrs after ovulation):—
LH surge expected (OPK positive ~24–36hrs before):—
BBT rise expected (confirms ovulation 1 day after):—
If 21-day cycle — ovulation day:—
If 35-day cycle — ovulation day:—
Ovulation & Fertility Insights
Visual day-by-day calendar showing your current cycle and the next one. Colour-coded by phase — period, fertile window, peak days, ovulation, and safe days. Uses your inputs from Tab 1.
Your Cycle Calendar
Enter your cycle details on the Ovulation Window tab to see your calendar.
Period
Fertile
Peak fertile
Ovulation
Safe days
Today

Uses your LMP and cycle length from Tab 1 to project all upcoming fertile windows and ovulation dates. The highlighted row is your next upcoming ovulation.

Next Ovulation Date
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All Fertile Windows in Your Plan
Cycle # Period Start Ovulation Peak Days Full Fertile Window If Conceived → EDD
Conception Planning
Days until next peak fertile window:—
If conceiving this cycle → expected due date:—
If conceiving next cycle → expected due date:—
Total fertile windows in plan:—
Recommended intercourse frequency:Every 1–2 days during fertile window
Fertility Planning Insights
Ovulation estimated at: LMP + (cycle length − luteal phase days). Fertile window: ovulation day − 5 days to ovulation day + 1 day (egg viable ~24 hrs; sperm survive up to 5 days). Luteal phase default = 14 days (typical range 12–16). All dates are estimates — actual ovulation varies with stress, illness, and cycle irregularity. Not a substitute for medical advice or contraception.