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Next period due − 14 days · Pregnancy period · 3-month predictionOvulation Calculator
Enter your last menstrual period start date and cycle length to instantly calculate your estimated ovulation date and fertile period.
📅 Estimated ovulation date🌸 Pregnancy period📆 3-Month Prediction⚡ Instant Results
📝 Enter period information
Last period start date
menstrual cycle28th
일
20th28th35 days45 days
💡 Ovulation Day = Next expected period date − 14 days. If your cycle is irregular, please use an ovulation test as well.
📊 Calculation result
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After entering menstrual information
Calculate Ovulation DatePlease press .
Expected ovulation date
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Start of the fertile period—
End of pregnancy period—
Day with the highest chance of pregnancy (ovulation day ±1)—
Next period due date—
📆 Prediction of the next 3 cycles
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Principles of Ovulation Day Calculation
Ovulation usually occurs 14 days before the next expected period. Since the luteal phase (14 days) following ovulation is constant regardless of the menstrual cycle, this method is used to estimate the date of ovulation.
Ovulation Day Formula
Ovulation Day = Last Period Start Date + Period Cycle − 14 days
Fertile period = 5 days before ovulation to 1 day after ovulation
Fertile period = 5 days before ovulation to 1 day after ovulation
💡 You can determine your ovulation date more accurately by checking for a surge in LH hormone in your urine using an ovulation test kit. Ovulation occurs approximately 24 to 36 hours after the LH surge.
Frequently Asked Questions
How do I calculate ovulation day?
The day of ovulation is calculated by subtracting 14 days from the expected date of the next period. If your menstrual cycle is 28 days, ovulation occurs on the 14th day after the start of your period. If your cycle is 30 days, ovulation occurs on the 16th day.
What is the probability of getting pregnant on the day of ovulation?
For healthy men and women, the probability of pregnancy is approximately 20–30 even if intercourse occurs on the day of ovulation. The probability of pregnancy is highest on the day before ovulation. If pregnancy does not occur for 6 months to 1 year, consultation with a specialist is recommended.
Do you have any ovulation symptoms?
During ovulation, cervical mucus becomes thick and clear, resembling egg white. Some women may also experience ovulation pain (pain in one side of the lower abdomen). When measuring basal body temperature (BBT), the temperature rises by 0.2 to 0.5°C after ovulation.