Pregnancy & Due Date Calculator

How is the due date calculated?

The globally accepted method is Naegele's rule: adding 280 days (40 weeks) to the first day of the last menstrual period. This rule assumes a regular 28-day cycle with ovulation on day 14.

If your cycle is longer than 28 days, ovulation happens later, so the due date is delayed by the same difference — which is exactly what the calculator adjusts automatically when you enter your real cycle length.

The three stages of pregnancy

Important supplements in each stage

• Folic acid: recommended a month before pregnancy and through the end of the first trimester to reduce the risk of neural tube defects.
• Iron: your need rises significantly from the second trimester to support increased blood volume.
• Vitamin D and calcium: to support both the mother's and the baby's bones.
• Omega-3 (DHA): to support the development of the baby's brain and retinas.

All doses must be determined under the supervision of your doctor. Some vitamins — like high-dose vitamin A — can be harmful during pregnancy, so never take any supplement on your own.

FAQ

How is the expected due date calculated?

Using Naegeles rule: 280 days (40 weeks) are added to the first day of the last menstrual period. The calculation assumes a regular 28-day cycle and adjusts automatically if your cycle is longer or shorter.

Is the calculated date accurate?

Only about 4 percent of women give birth on the exact expected date, and most births happen within a two-week window before or after it. An ultrasound in the first trimester remains the most accurate way to date the pregnancy.

Which supplements matter during pregnancy?

Folic acid is recommended from one month before pregnancy through the end of the first trimester to reduce the risk of neural tube defects, alongside iron, vitamin D and omega 3 (DHA). Doses should be set under your doctor supervision.