Pregnancy Due Date Calculator — When Is Your Baby Due?

What is a Pregnancy Due Date Calculator?

A pregnancy due date calculator (प्रेगनेंसी ड्यू डेट कैलकुलेटर) estimates the day your baby is expected to arrive — the estimated date of delivery (EDD). It also tells you how many weeks and days pregnant you are today, which trimester you are in, and when important check-ups and scans usually take place. Doctors and midwives use the same basic method, so the result is a useful starting point for planning your antenatal care, maternity leave and preparations at home.

This free calculator offers three ways to estimate the date: from the first day of your last period (with your cycle length), from a known conception date, or from an IVF embryo transfer. Everything runs in your browser — the dates you enter are never sent anywhere.

Key Features

• Three methods: last menstrual period (LMP), conception date and IVF transfer (day-3 or day-5 embryo).
• Cycle-length adjustment for cycles from 20 to 45 days.
• Weeks and days pregnant on any date you choose.
• Trimester and days to go.
• Estimated conception date.
• Milestone table with dates for the NT scan, anatomy scan, glucose screening and full term.

How to Use It

1. Choose Last period, Conception date or IVF transfer.
2. Pick the date. For the period method, use the first day of bleeding, not the last.
3. Enter your average cycle length (from the first day of one period to the first day of the next).
4. For IVF, choose a day-3 or day-5 embryo.
5. Read your due date, how far along you are, the trimester and the milestone dates.

How the Due Date is Calculated

Naegele's rule (from your last period)

The traditional method adds 280 days — 40 weeks — to the first day of your last menstrual period (LMP). It assumes a 28-day cycle with ovulation around day 14. A handy shortcut gives the same answer: add one year, subtract three months and add seven days.

Example: last period started on 1 January 2026 → due date 8 October 2026.

Adjusting for your cycle length

If your cycle is longer than 28 days, ovulation usually happens later, so the due date moves later by the difference. A 32-day cycle adds 4 days: with the same 1 January LMP, the due date becomes 12 October 2026. A 25-day cycle moves it 3 days earlier.

From a conception date

If you know when you conceived, add 266 days (38 weeks). Conception on 15 January 2026 gives the same 8 October due date.

After IVF

For IVF the transfer date and the embryo's age are known exactly. Add 261 days to a day-5 blastocyst transfer, or 263 days to a day-3 embryo transfer. A day-5 transfer on 20 January 2026 points to 8 October 2026; a day-3 transfer on the same date points to 10 October.

Due Date Quick Reference

Understanding "Weeks Pregnant"

Pregnancy is counted in gestational weeks from the first day of the last period — about two weeks before conception actually happens. That is why, when a period is first missed, you are already considered about 4 weeks pregnant. Doctors write gestational age as weeks plus days, such as "12+3", meaning 12 weeks and 3 days.

Forty weeks is a little over nine calendar months. If you count in four-week "months", it comes to ten — which is why some people describe pregnancy as lasting ten months.

The Three Trimesters

Exact schedules differ between hospitals and countries. Your doctor or midwife will tell you which tests are recommended for you and when.

How Accurate is a Due Date?

A due date is an estimate, not an appointment. Only around 4–5% of babies are born on the exact day. Most births happen within two weeks either side of it. Several things affect accuracy:

• Irregular cycles make the period-based method less reliable.
• Uncertain dates — if you are not sure when your last period started.
• Ovulation timing varies even in regular cycles.
• Ultrasound dating in the first trimester measures the baby directly and is generally the most accurate method. If it differs from your period-based date by more than a few days, doctors usually adopt the scan date.

Term Definitions

• Preterm: before 37 weeks.
• Early term: 37+0 to 38+6 weeks.
• Full term: 39+0 to 40+6 weeks.
• Late term: 41+0 to 41+6 weeks.
• Post-term: 42 weeks and beyond.

If your pregnancy goes past the due date, your care team will discuss monitoring and options with you. Never hesitate to contact them if you notice reduced baby movements, bleeding, fluid leaking, severe headaches or regular painful contractions before 37 weeks.

Planning Around Your Due Date

• Book antenatal care early — ideally as soon as you know you are pregnant.
• Maternity leave: Indian law provides up to 26 weeks of paid maternity leave for eligible women employees for the first two children (12 weeks from the third child), of which up to 8 weeks can be taken before the expected delivery date. Your due date is what HR uses to plan this, so share it early and check your employer's policy and eligibility conditions.
• Hospital bag: have it ready by around 36 weeks.
• Travel: airlines often restrict flying late in pregnancy — check their rules and your doctor's advice.
• Paperwork: keep your antenatal card, reports and ID together.

Healthy Pregnancy Basics

Alongside regular check-ups, doctors commonly advise folic acid (ideally started before conception), a balanced diet, enough water, gentle activity if your doctor agrees, adequate rest and avoiding alcohol and smoking. Our Water Intake Calculator includes an option for pregnancy, and the BMI Calculator shows your pre-pregnancy BMI, which doctors use to guide healthy weight gain. Always follow the advice of your own doctor.

Using the "Check Progress On" Date

The calculator normally shows how far along you are today, but you can pick any date. This is useful for questions like "How many weeks will I be at my sister's wedding?" or "Which trimester will I be in when I travel?" Change the date and the weeks, trimester and days-to-go update instantly.

Common Mistakes

• Using the last day of the period instead of the first.
• Ignoring cycle length when cycles are much longer or shorter than 28 days.
• Treating the due date as fixed — prepare for any day from 37 weeks.
• Relying on the calculator instead of a doctor — it is a planning aid, not a diagnosis.

Quick Glossary

• LMP: first day of the last menstrual period.
• EDD: estimated date of delivery.
• Gestational age: weeks and days counted from the LMP.
• Blastocyst: a 5–6 day old embryo used in many IVF transfers.
• NT scan: nuchal translucency ultrasound, usually at 11–13+6 weeks.

Why Use This Calculator?

It gives you the same estimate your doctor starts with, adjusts for your own cycle, works for IVF pregnancies and lays out the key milestone dates in one table you can copy. It is free, private and needs no sign-up. If you are trying to conceive, our Ovulation Calculator shows your fertile window, and the Date Difference Calculator counts days between any two dates.

Pregnancy Due Date Calculator — Key Facts

Frequently Asked Questions

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