Find your fertile window, peak ovulation date and best days to conceive — with a 3-month fertility calendar and next 3 cycle predictions.
⚕️This tool is for general information only and is not a substitute for medical advice. Results are based on average cycle patterns and may not reflect individual variation. Consult your doctor for personalised fertility guidance.
28d
days
days
days
🥚Ovulation Day——
🌿Fertile Window—6-day window
📅Next Period——
—Peak Fertile Day
—Days to Ovulation
—Luteal Phase
—Current Phase
Your cycle timeline — day 1 to day 28
Period
Follicular
Fertile Window
Ovulation
Luteal
3-Month fertility calendar
Next 3 predicted cycles
CyclePeriod startsOvulationFertile window
🌡️
Track basal body temperature
Your BBT rises 0.2–0.5°C after ovulation. Track it daily (before getting out of bed) to confirm ovulation and learn your patterns over several months.
💧
Watch for cervical mucus changes
During your fertile window, cervical mucus becomes clear, slippery and stretchy — like raw egg white. This is the most fertile type of mucus.
🧪
Use ovulation predictor kits
OPKs detect the LH surge that happens 24–36 hours before ovulation. Start testing a few days before your predicted fertile window for best results.
❤️
Timing intercourse
For best chances of conception, have intercourse every 1–2 days during your fertile window, especially the 2 days before ovulation and ovulation day itself.
How the ovulation cycle works
A typical menstrual cycle is divided into four phases. The timing of ovulation — and therefore the fertile window — is the key to understanding fertility. Ovulation occurs when an egg is released from the ovary, which can only happen during a short window each cycle.
🩸MenstrualDays 1–5 (avg)
🌱FollicularDays 6–13 (avg)
🥚OvulatoryAround Day 14
🌙LutealDays 15–28 (avg)
Ovulation is calculated as: Ovulation day = Cycle length − Luteal phase length. The fertile window is the 5 days before ovulation plus ovulation day. The egg survives 12–24 hours, but sperm can survive up to 5 days in the reproductive tract.
Every woman's cycle is unique and can vary month to month. Stress, illness, travel, and weight changes can all affect timing. Tracking multiple cycles gives a more accurate picture of your personal pattern.
Frequently asked questions
How accurate is this ovulation calculator?
This calculator provides an estimate based on average cycle patterns. It works well for women with regular cycles. However, ovulation can vary by a few days even in regular cycles, and irregular cycles make predictions less reliable. For the most accurate results, combine this calculator with basal body temperature tracking and ovulation predictor kits.
What is the fertile window?
The fertile window is the 6-day period during your cycle when pregnancy is possible — the 5 days before ovulation and the day of ovulation itself. This is because sperm can survive up to 5 days in the female reproductive tract, and the egg survives for 12–24 hours after ovulation. The 2 days before ovulation and ovulation day itself are the most fertile days.
What is the luteal phase?
The luteal phase is the second half of your cycle, starting after ovulation and ending with your next period. The corpus luteum (remnant of the follicle) produces progesterone to prepare the uterine lining for potential implantation. A typical luteal phase lasts 12–16 days. A short luteal phase (under 10 days) can make it harder to conceive and may warrant medical evaluation.
Can I get pregnant outside the fertile window?
Pregnancy outside the estimated fertile window is unlikely but not impossible — cycles can vary, and ovulation timing is not always predictable. This is why using ovulation predictor kits alongside calendar methods gives a more complete picture. There is no completely "safe" day in a natural cycle.
What if my cycle is irregular?
Irregular cycles (cycles that vary by more than 7–9 days) make calendar-based ovulation prediction less reliable. For irregular cycles, it's best to track basal body temperature daily, use ovulation predictor kits, and monitor cervical mucus changes. Consult a healthcare provider if irregularity is ongoing, as it can sometimes indicate an underlying hormonal condition.