Calculadora de Data Provável do Parto
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
DPP = DUM + 280 dias
About this calculator
The Due Date Calculator estimates the baby's likely birth date using Naegele's Rule. The calculation takes the first day of the last menstrual period (LMP) and adds 280 days, which corresponds to 40 weeks of pregnancy. This tool is useful for pregnant women and healthcare professionals to plan prenatal care and prepare for delivery.
How it works: enter the date of the first day of your last menstrual period. The calculator automatically adds 280 days to obtain the estimated due date. This method assumes regular 28-day menstrual cycles and is an estimate, not a guarantee. Only about 5% of babies are born exactly on the calculated date.
When to use: ideal for women with regular cycles who know their LMP. Useful for scheduling exams, planning maternity leave, and preparing the baby's belongings. Note: women with irregular cycles or who do not remember their LMP should consult a doctor for a more accurate estimate, usually via ultrasound.
Precautions: the calculated date is an estimate. Delivery can occur between 37 and 42 weeks of pregnancy. It does not replace medical follow-up. If you have doubts about the date or symptoms, consult an obstetrician.
Frequently asked questions
What if my cycle is not 28 days?
Naegele's Rule assumes 28-day cycles. If your cycle is different, the estimated date may not be accurate. Consult your doctor for adjustments.
Can the due date change?
Yes, especially if you have an early ultrasound. The doctor may adjust the date based on the baby's size.
How many weeks is a normal pregnancy?
A full-term pregnancy lasts between 37 and 42 weeks. The due date is for 40 weeks.
What is LMP?
LMP stands for Last Menstrual Period. It is the first day of your last menstrual period before pregnancy.
Can I use this calculator if I don't remember my LMP?
No, the calculator needs the LMP. If you don't remember, consult a doctor to estimate the date via ultrasound.