Estimate a pregnancy due date from the date of your last menstrual period or a known conception date, and see the current gestational age in weeks and days plus the trimester. This is an approximate reference, not medical advice; for any health concern or emergency, contact your pediatrician or emergency services, and follow WHO, CDC or your local health authority guidance.
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How to Use the Due Date Calculator
Choose whether to calculate from your last menstrual period or a known conception date, enter the start date, then press Calculate Due Date. For the LMP method you can also adjust the average cycle length.
Reading the result
The due date uses Naegele's rule: 280 days from the LMP, adjusted for cycle length.
The conception method counts 266 days from the conception date.
Gestational age is reported in weeks and days, with the trimester that corresponds to it.
Only about 4% of babies arrive on the exact due date; it is a midpoint, not a deadline.
Features
Works from a last menstrual period or a conception date
Adjusts for average cycle length
Shows gestational age in weeks and days and the trimester
This is an approximate reference, not medical advice; for any health concern or emergency, contact your pediatrician or emergency services, and follow WHO, CDC or your local health authority guidance.
All processing runs locally in your browser. Your data is not uploaded to any server.
An early ultrasound is the most accurate way to date a pregnancy. Treat this figure as a reference to discuss with your midwife or doctor.