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Pregnancy Calculator

Calculate your pregnancy due date accurately with our advanced Pregnancy Calculator! Whether based on your last period (LMP), IVF transfer date, conception date, or ultrasound results, get personalized estimates, trimester timeline, and essential pregnancy tips. Perfect for expecting moms!

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Pregnancy Calculator

Enter your information to estimate key pregnancy dates and get personalized tips.

Your Pregnancy Timeline

Enter your information to see your personalized pregnancy timeline and tips.

Due Date Calculator

Get your accurate pregnancy due date based on last period, conception date, or IVF transfer with personalized trimester.

Multiple Calculation

Calculate using LMP, ultrasound dates, conception date, or IVF transfer with cycle length adjustments for precision.

Pregnancy Progress Tracker

See your current week, trimester, and percentage completed with personalized tips for each stage.

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FAQ: Frequently Asked Questions

What is Average Cycle Length?

Average Cycle Length refers to the total number of days from the first day of a woman’s period to the first day of her next period. Typically, it is taken to be 28 days, but in reality it can be anywhere from 21 to 35 days. Count the days from the first day of your period to the first day of your next period. Inputting your Real Cycle Length is very important for accurate pregnancy calculations!

How accurate are pregnancy calculator?

Pregnancy calculators provide estimates based on standard calculations, but only about 5% of women deliver on their exact due date. The calculator assumes a 28-day cycle with ovulation on day 14, which may not match your unique cycle. Ultrasound dating in the first trimester is more accurate, typically within 3-5 days. Your healthcare provider will give you the most reliable due date based on your medical history and examinations.

Why does my due date change after an ultrasound?

Ultrasounds in the first trimester measure the baby’s size to estimate gestational age more accurately than menstrual dates, especially if your cycles are irregular. If there’s more than a 5-7 day difference between your LMP-based due date and the ultrasound measurement, doctors typically adjust your due date. Later ultrasounds are less reliable for dating as babies grow at different rates.
Can I use a pregnancy calculator if I have irregular periods?
Yes, but you’ll get more accurate results if you know your ovulation date or use ultrasound dating. With irregular cycles, the standard “LMP + 280 days” calculation may be off because ovulation timing varies. Try tracking ovulation with temperature charts or kits, or ask your doctor for a dating ultrasound between 8-12 weeks for better accuracy.
How does IVF affect due date calculations?
With IVF pregnancies, the conception date is precisely known, making due date calculation more accurate. For 3-day embryo transfers, subtract 3 days from the transfer date and add 266 days. For 5-day transfers, subtract 5 days then add 266 days. IVF calculators account for this automatically, giving you a more reliable due date than LMP-based calculations.

What's the difference between gestational age and fetal age?

Gestational age counts pregnancy from the first day of your last period (about 2 weeks before conception), while fetal age starts at conception. Doctors use gestational age because most women know their LMP but not conception date. When a calculator says “8 weeks pregnant,” your baby’s fetal age is actually about 6 weeks.

Why do pregnancy calculators give different results?

Different calculators may use slightly different algorithms or assumptions about cycle length and luteal phase. Some account for variable cycle lengths while others assume 28 days. Ultrasound-based calculators might use different growth charts. The most reliable calculators let you input your specific information rather than using averages.

Can a pregnancy calculator tell me when I conceived?

Yes, if you know your LMP and have regular cycles, conception typically occurs about 11-21 days after your period starts (day 14 for average cycles). The calculator estimates this window based on your cycle length. However, sperm can live 3-5 days, so the actual conception date might span several days around ovulation.

How do pregnancy weeks and months correspond?

Pregnancy lasts about 40 weeks but only 9 calendar months because months have 4-5 weeks. The first month includes weeks 1-4, second month weeks 5-8, and so on. Trimesters divide the 40 weeks into three phases: first (weeks 1-13), second (weeks 14-26), and third trimester (weeks 27-40).
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