Pregnancy Due Date & Ovulation Calculator
Estimate your baby's due date, current pregnancy week, and trimester from your last period — or find your most fertile days with the ovulation calculator.
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孕周
受孕时间约在
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已怀孕天数
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距预产期还有
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完成百分比
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预计排卵日
易孕期日历
易孕期开始
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易孕期结束
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预计下次月经
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How the due date is estimated
Using Naegele's rule, your estimated due date is 280 days (40 weeks) from the first day of your last menstrual period, adjusted for your average cycle length. Most babies arrive within two weeks of this date.
Simple, private, and free
Enter your last period date and cycle length to get an instant due date, current pregnancy week, trimester, and fertile window. All calculations run in your browser — nothing is stored.
Why use our Pregnancy & Ovulation Calculator?
Two calculators in one
Due date and ovulation tools in a single tool.
Visual progress ring
See your pregnancy week and percent complete at a glance.
Fertile window calendar
A clear 7-day strip highlighting your most fertile days.
Free to use
No sign-up, fees, or download required.
Free Online Pregnancy Due Date & Ovulation Calculator
Use the DailyOnWeb pregnancy due date calculator to estimate your baby's arrival date, current pregnancy week, and trimester from the first day of your last menstrual period (LMP). Switch to the ovulation calculator to find your fertile window, estimated ovulation day, and next expected period — useful whether you are trying to conceive or simply tracking your cycle.
How to calculate your pregnancy due date
Enter the first day of your last period and your average menstrual cycle length. The calculator applies Naegele's rule — adding 280 days (40 weeks) to your LMP and adjusting for cycles longer or shorter than the typical 28 days — to estimate your due date, conception date, current week of pregnancy, and trimester.
How the ovulation calculator works
Ovulation typically occurs about 14 days before your next period begins. Based on your last period date and cycle length, this ovulation calculator estimates your ovulation day and a five-day fertile window leading up to it — the days when you are most likely to conceive — plus your next expected period date.
What this pregnancy and ovulation tool can tell you
- Your estimated due date and how many weeks and days pregnant you are today.
- Which trimester you are currently in, with a visual pregnancy progress bar.
- An estimated conception date and the percentage of your pregnancy completed.
- Your fertile window, ovulation day, and next expected period for cycle and ovulation tracking.
This due date calculator and ovulation calculator are for general informational and planning purposes only and do not replace medical advice. Every pregnancy and cycle is different — always confirm dates and any fertility or prenatal concerns with your doctor or midwife.
常见问题 （常见问题）
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