Pregnancy Due Date Calculator
Estimate your baby's due date from last menstrual period (LMP) or conception date. Includes gestational age and trimester.
Pregnancy details
Most people have a 28-day cycle. Adjust if yours is shorter or longer.
Estimated due date
Wednesday, January 13, 2027
224 days to go
Currently
8 weeks 0 days
Trimester
1st
Conception (est.)
Apr 22, 2026
Informational only, not a substitute for medical care.
Frequently Asked Questions about the Pregnancy Due Date Calculator
How is the due date calculated?
From your last menstrual period (LMP), it uses Naegele's rule: LMP plus 280 days, adjusted for cycle length. From conception, it adds 266 days. Gestational age is measured from LMP, about 14 days before conception.
How accurate is the estimated due date?
Only about 5% of babies arrive on the exact due date. Roughly 80% are born within 2 weeks of it (37 to 42 weeks). Early ultrasound dating, especially in the first trimester, is more accurate than LMP for irregular cycles. This is an estimate. Consult your doctor.
What are the trimesters and how long is each?
First trimester runs weeks 1 to 12, second trimester weeks 13 to 26, third trimester weeks 27 to birth. Each trimester has different developmental milestones and prenatal care recommendations.
When should I see a doctor?
Book a first prenatal visit within 8 to 10 weeks of your LMP. Seek immediate care for heavy bleeding, severe abdominal pain, sudden swelling, severe headaches, or reduced fetal movement after 28 weeks. This calculator does not replace medical care.
Does cycle length affect the due date?
Yes, if you use LMP. Naegele's rule assumes a 28-day cycle. Longer or shorter cycles shift ovulation, so the calculator adjusts the due date by the difference between your cycle and 28 days. Conception-based dating skips this step.
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