Calculate Your Due Date, Current Week, and Pregnancy Milestones
To calculate your pregnancy due date, add 280 days (40 weeks) to the first day of your last menstrual period (LMP). For example, if your LMP was January 1st, your due date would be October 8th. This is based on Naegele's rule, which assumes a 28-day menstrual cycle. Your healthcare provider may adjust this date based on ultrasound measurements for more accuracy.
This calculator uses the standard Naegele's rule and provides week-by-week pregnancy information following Canadian prenatal care guidelines.
This Pregnancy Calculator calculates your estimated due date using Naegele's rule (LMP + 280 days) and provides detailed information about your pregnancy progress week by week. It follows guidelines from the Society of Obstetricians and Gynaecologists of Canada (SOGC) and Health Canada recommendations for prenatal care.
Standards: Naegele's Rule (LMP + 280 days), SOGC Guidelines, Health Canada Prenatal Standards, International Gestational Age Assessment
Based on established medical guidelines from Health Canada and SOGC
Track your pregnancy progress week by week
See exact dates for all three trimesters
Track key medical appointments and development stages
Get your pregnancy timeline and milestones immediately
No registration required, completely free pregnancy calculator
Naegele's rule estimates the expected delivery date by adding 280 days to the last menstrual period.
Approximately 5% of babies arrive on the calculated date; ultrasound dating can refine the estimate.
Naegele's Rule
EDD = LMP + 280 days
Pregnancy is calculated as <strong>40 weeks (280 days)</strong> from the first day of your last menstrual period (LMP), even though conception typically occurs about 2 weeks after LMP. This is why you're considered '2 weeks pregnant' at conception.
The pregnancy is divided into three <strong>trimesters</strong>: First trimester (weeks 1-12), second trimester (weeks 13-26), and third trimester (weeks 27-40). Each trimester has distinct developmental milestones and common symptoms.
Our pregnancy calculator helps you determine your due date, current week, and important milestones. Follow these simple steps:
Select from Last Menstrual Period (LMP), conception date, known due date, ultrasound date, or IVF transfer date.
Input the relevant date for your chosen method. For ultrasound, also enter the gestational age at the time of the scan.
View your estimated due date, current pregnancy week, trimester dates, and important milestones at a glance.
Use the milestone timeline to prepare for key prenatal appointments, screening tests, and developmental stages.
Pregnancy is divided into three trimesters, each with distinct physical changes, fetal development milestones, and prenatal care needs.
Rapid cell division and organ formation occur. Common symptoms include nausea, fatigue, and breast tenderness. First prenatal visit and screening tests typically happen during this period.
Often called the 'golden period' as nausea subsides. The anatomy ultrasound is performed around weeks 18-22. You may begin to feel fetal movement (quickening) around week 20.
The baby gains weight rapidly and organs mature for life outside the womb. Prenatal visits increase in frequency. Preparation for labour and delivery becomes the focus.
Due dates are estimates based on averages. Every pregnancy is unique, and actual delivery may occur 2 weeks before or after the estimated date.
This calculator is for informational purposes only. Always consult your healthcare provider for personalized medical advice and pregnancy care.
Calculations based on LMP assume a regular 28-day cycle. If your cycles are irregular, an ultrasound may provide a more accurate due date.
Factors such as maternal age, health conditions, and multiple pregnancies can affect timing. Your midwife or obstetrician will adjust care plans based on your specific situation.
Book your first appointment around 8-10 weeks. Early prenatal care allows for timely screening tests and establishes a baseline for monitoring your pregnancy. In Canada, midwives and obstetricians both provide excellent care.
Start taking a prenatal vitamin with at least 400-600 mcg of folic acid before conception and throughout pregnancy. Folic acid significantly reduces the risk of neural tube defects.
Most pregnant women can safely continue moderate exercise. Walking, swimming, and prenatal yoga are excellent choices. Aim for 150 minutes per week, but always consult your healthcare provider first.
Focus on whole grains, lean proteins, fruits, vegetables, and dairy. Avoid high-mercury fish, unpasteurized products, and undercooked meat. Stay hydrated and listen to your body's hunger cues.
Keep a pregnancy journal noting important dates, test results, and when you first feel movement (quickening). This information helps your healthcare provider monitor development and can be meaningful to look back on.
Remember that only 5% of babies arrive on their due date. Prepare for your baby to come anytime from 37-42 weeks. Have your hospital bag packed by 36 weeks and stay in close contact with your healthcare provider.
The age of the pregnancy calculated from the first day of the last menstrual period (LMP). This is typically about 2 weeks more than the actual age of the embryo or fetus.
The estimated date when your baby will be born, calculated as 280 days (40 weeks) from the first day of your last menstrual period. Only about 5% of babies are born exactly on their due date.
A period of three months during pregnancy. The first trimester is weeks 1-12, the second trimester is weeks 13-26, and the third trimester is weeks 27-40.
The date when the egg was fertilized by sperm. This typically occurs about 2 weeks after the first day of your last menstrual period, around the time of ovulation.
Using ultrasound measurements to estimate the due date. First-trimester ultrasounds are the most accurate method for dating pregnancy, with an accuracy of ±5-7 days.
Important Medical Disclaimer
This pregnancy calculator provides estimates only. Your due date is calculated using Naegele's rule (LMP + 280 days), which assumes a regular 28-day menstrual cycle with ovulation on day 14. Only ultrasound dating confirmed by an obstetrician or midwife provides accurate gestational age assessment.
This calculator does not replace prenatal care. All pregnancies should involve regular visits with a Canadian healthcare provider (obstetrician, midwife, or family physician) for proper monitoring and care.
Consult a Canadian Healthcare Professional Immediately If:
Canada has a comprehensive prenatal care system. Regular prenatal visits are essential for monitoring both maternal and fetal health throughout pregnancy.
The Society of Obstetricians and Gynaecologists of Canada (SOGC) recommends regular prenatal visits starting in the first trimester, with increasing frequency as the due date approaches.
A dating ultrasound between 11-14 weeks provides the most accurate gestational age. This may adjust your due date from the LMP-based calculation used by this tool.
Each Canadian province offers prenatal care programs and resources. Contact your provincial health authority for information about available services and support.
Health Canada recommends prenatal vitamins including folic acid, and provides specific nutrition guidance for pregnant Canadians through Canada's Food Guide.
SOGC Recommendation: The Society of Obstetricians and Gynaecologists of Canada recommends that all pregnant individuals in Canada receive comprehensive prenatal care from a qualified healthcare provider. Contact your family physician, obstetrician, or midwife as soon as you suspect pregnancy.
This calculator is based on the following authoritative sources and research:
Canadian Medical Association Journal (2026)
View SourceImportant Note: This calculator provides estimates based on standard pregnancy calculations. Every pregnancy is unique, and due dates can vary. Always consult with your healthcare provider for personalized medical advice and accurate dating through ultrasound.
Find answers to common questions about pregnancy dating, due dates, and prenatal care in Canada
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