Free Pregnancy Due Date Calculator
Enter the first day of your last menstrual period to estimate your due date and see the trimester breakdown.
The Pregnancy Due Date Calculator estimates a due date from the first day of the last menstrual period and breaks the pregnancy into trimesters. It is a planning aid, not a medical diagnosis.
How is a due date estimated?
A pregnancy due date is typically estimated by adding 280 days (40 weeks) to the first day of a woman's last menstrual period (LMP). This method, known as Naegele's rule, is the standard approach used by healthcare providers worldwide. It assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. While this provides a useful estimate, it's important to remember that actual delivery dates can vary based on individual factors.
Pregnancy is divided into three trimesters, each marking different stages of fetal development. The first trimester spans from conception to week 13, during which major organs and structures form. The second trimester (weeks 14-27) is often considered the most comfortable, with reduced nausea and increased energy. The third trimester (weeks 28-40) involves rapid growth and preparation for birth. Knowing your estimated due date helps healthcare providers monitor your pregnancy and plan appropriate care.
This pregnancy due date calculator provides more than just the estimated delivery date. It also calculates your current gestational age in weeks and days, helping you understand how far along your pregnancy has progressed. The tool displays which trimester you're currently in and provides the date ranges for each trimester. All calculations are performed instantly in your browser with no data collection, making it a fast and private way to estimate your due date.
How to use this Pregnancy Due Date Calculator
- Enter the first day of your last menstrual period (LMP) using the date picker.
- The calculator will automatically display your estimated due date based on the 280-day rule.
- View your current gestational age in weeks and days from the LMP to today.
- See which trimester you're currently in and the date ranges for each trimester.
- Use this information to discuss your pregnancy timeline with your healthcare provider.
FAQ
How is the due date calculated?
The due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period. This is the standard method used by healthcare providers.
Is the due date exact?
The due date is an estimate, not an exact prediction. Only about 5% of babies are born on their exact due date. Most babies are born between 37 and 42 weeks of pregnancy.
Is my due date information private and not shared?
No, this pregnancy calculator runs entirely in your browser. Your date input is processed locally with no data sent to any server or stored anywhere.
Is this calculator free?
Yes, this pregnancy due date calculator is completely free to use with no hidden fees or subscriptions required.