Due Date Calculator — and the Whole Schedule After It
Every other calculator gives you one date and stops. Enter the first day of your last period and get the due date plus every antenatal visit, both scans, the Td and Tdap windows and when iron and calcium start — as real calendar dates.
The standard formula assumes 28 days. A longer or shorter cycle moves ovulation, and the due date with it. Leave it at 28 if you are not sure.
Nothing you enter is sent anywhere. It is worked out in your browser and forgotten when you close the tab.
Enter a date to see the schedule
You will get the due date, how far along you are today, and every antenatal visit, scan and vaccine as real calendar dates.
Questions people ask
How is a pregnancy due date calculated?
By Naegele's rule: 280 days, or 40 weeks, from the first day of your last menstrual period. That formula assumes a 28-day cycle, so if your cycle is longer or shorter the due date shifts by the difference — a 32-day cycle moves it four days later.
Why does the count start from my last period and not conception?
Because the date of the last period is something you can know, and the date of conception usually is not. Counting from the last period means you are already considered about two weeks pregnant at conception. Every clinical schedule uses this same convention, which is why the weeks here match what your doctor says.
How accurate is a due date?
It is an estimate, not an appointment. Only about one baby in twenty is born on the due date itself, and a full-term birth is anything from 37 to 42 weeks. A dating scan in the first trimester is more accurate than a calculation from your last period, so if your doctor has given you a scan-based date, use that one.
How many antenatal visits are needed?
WHO's 2016 model recommends eight antenatal contacts, at roughly 12, 20, 26, 30, 34, 36, 38 and 40 weeks. India's MoHFW sets a minimum of four. This calculator lays out the eight WHO contacts and marks which ones are the MoHFW minimum, so it is useful whichever schedule your hospital follows.
When are the pregnancy scans done?
The dating and NT scan is done between 11 and 13 weeks, and the anomaly scan, often called TIFFA, between 18 and 22 weeks. Both are fixed windows that cannot be done later, so they are the two appointments worth booking well ahead. A growth scan usually follows between 28 and 32 weeks.
When are Td and Tdap given in pregnancy?
Td, the tetanus-diphtheria vaccine, is given as early as possible in the second trimester with a second dose four weeks later, though a single booster may be enough if you were immunised in a previous pregnancy. Tdap is recommended between 27 and 36 weeks so whooping-cough antibodies reach the baby before birth.
Is this calculator medical advice?
No. It applies published guideline windows to the date you enter and shows the result as calendar dates. It does not interpret symptoms, scans or test results. Your doctor's plan always takes precedence over this page.