Pregnancy & Maternal Health

Pregnancy Due Date Calculator

Find your due date, how many weeks pregnant you are, your trimester and when your key scans fall — made for Indian mothers-to-be.

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Enter your details

Takes 20 seconds · No login required · Your dates never leave your device

Your name (optional)

How do you want to calculate?

First day of your last period

Average cycle length (days)

days

Usually 28. Enter a number from 21 to 35.

Your Pregnancy Result

Due date & week — Naegele's rule

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of 40 weeks

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First Second Third

Weeks 1–13 14–27 28–40

Due Date

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Days to Go

—days

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Baby This Week

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ℹ

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Key dates for your pregnancy

⚠ See a doctor or go to the nearest hospital straight away if you have: vaginal bleeding, leaking of fluid, severe tummy pain, a severe headache with blurred vision, sudden swelling of the face or hands, fever, vomiting that stops you keeping fluids down, or if your baby moves much less than usual.

Medical Disclaimer: This calculator is for informational purposes only and is not a substitute for professional medical advice. Your due date is an estimate — only about 5 in 100 babies arrive on it. Please follow the dates and advice given by your own doctor.

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Data Sources & Methodology

Clinical guidance and reference data behind this calculator

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Methods for Estimating the Due Date

ACOG · Committee Opinion · 2017

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WHO Antenatal Care Guidelines

World Health Organization · 2016

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Pregnancy Health Topics

NIH · MedlinePlus

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ICMR-NIN Nutrition Guidelines

National Institute of Nutrition

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Surakshit Matritva Abhiyan

Ministry of Health & Family Welfare

What is a Due Date Calculator?

Pregnancy Due Date Calculator — How Many Weeks Pregnant Am I?

A pregnancy due date calculator estimates your expected date of delivery (EDD) and tells you how many weeks pregnant you are today. It is the first tool most women use after a positive pregnancy test.

Enter the first day of your last period, your conception date or your IVF embryo transfer date in the calculator above — no login, no signup. This pregnancy week calculator also shows your trimester, your pregnancy month, the size of your baby this week and the usual dates for your dating scan, NT scan, anomaly scan and glucose test. It works as a due date calculator by LMP, a conception date calculator and an IVF due date calculator in one place.

Nothing you type is sent to our server. The calculation runs entirely in your browser.

How to Use This Pregnancy Calculator

Pick your method

Choose last period date, conception date or IVF transfer date.

Enter the date

For the last-period method, also add your usual cycle length (28 days if unsure).

Get your due date

See your due date, weeks and days pregnant, trimester and days to go instantly.

Plan your checkups

Use the key dates list to plan your scans, and confirm them with your doctor.

Due Date Formula

How Your Due Date Is Calculated — Naegele's Rule and Other Methods

Doctors count pregnancy from the first day of your last menstrual period (LMP), not from the day you conceived. A full-term pregnancy is 40 weeks, or 280 days.

Naegele's rule

Due date = First day of last period + 280 days

Adjusted for cycle length: add (your cycle length − 28) days. Conception date: add 266 days. IVF transfer: add 261 days (Day 5) or 263 days (Day 3).

Worked Examples

Example: if the first day of your last period is 5 Jan 2026 and your cycle is 28 days long, your due date is 12 Oct 2026. With a longer or shorter cycle the date shifts, as shown below.

First day of last period	Cycle length	Estimated due date
5 Jan 2026	28 days	12 Oct 2026
12 Mar 2026	28 days	17 Dec 2026
20 May 2026	32 days	28 Feb 2027
1 Aug 2026	26 days	6 May 2027

Last period: 5 Jan 2026
Cycle: 28 days
Due date: 12 Oct 2026

Last period: 12 Mar 2026
Cycle: 28 days
Due date: 17 Dec 2026

Last period: 20 May 2026
Cycle: 32 days
Due date: 28 Feb 2027

Last period: 1 Aug 2026
Cycle: 26 days
Due date: 6 May 2027

Why a Due Date Can Be Off

The last-period method assumes ovulation on day 14 of a regular cycle. If your periods are irregular, or you are not sure of the date, the estimate can be a week or more out. In that case an early ultrasound is more reliable, and your doctor may revise your due date after your dating scan. Always follow the date your doctor gives you.

Weeks, Months & Trimesters

Pregnancy Weeks to Months Chart and Trimesters

Pregnancy is 40 weeks long, which is about 9 months and 1 week. Because months vary in length, doctors always talk in weeks. Use this chart to convert weeks to pregnancy months.

Pregnancy Weeks to Months

Pregnancy month	Weeks	Trimester
Month 1	Weeks 1 to 4	First
Month 2	Weeks 5 to 8	First
Month 3	Weeks 9 to 13	First
Month 4	Weeks 14 to 17	Second
Month 5	Weeks 18 to 21	Second
Month 6	Weeks 22 to 26	Second
Month 7	Weeks 27 to 30	Second / Third
Month 8	Weeks 31 to 35	Third
Month 9	Weeks 36 to 40	Third

Month 1 · Weeks 1 to 4
Trimester: First

Month 2 · Weeks 5 to 8
Trimester: First

Month 3 · Weeks 9 to 13
Trimester: First

Month 4 · Weeks 14 to 17
Trimester: Second

Month 5 · Weeks 18 to 21
Trimester: Second

Month 6 · Weeks 22 to 26
Trimester: Second

Month 7 · Weeks 27 to 30
Trimester: Second / Third

Month 8 · Weeks 31 to 35
Trimester: Third

Month 9 · Weeks 36 to 40
Trimester: Third

The Three Trimesters

Trimester	Weeks	Months	What usually happens
First	1 to 13 weeks 6 days	Months 1 to 3	Organs form; nausea and tiredness are common; first antenatal visit and dating scan
Second	14 to 27 weeks 6 days	Months 4 to 7	Energy returns; baby movements felt; anomaly scan; glucose test
Third	28 weeks to birth	Months 7 to 9	Rapid growth; more frequent checkups; birth preparation

First trimester · 1 to 13 weeks 6 days · Months 1 to 3
Organs form; nausea and tiredness are common; first antenatal visit and dating scan.

Second trimester · 14 to 27 weeks 6 days · Months 4 to 7
Energy returns; baby movements felt; anomaly scan; glucose test.

Third trimester · 28 weeks to birth · Months 7 to 9
Rapid growth; more frequent checkups; birth preparation.

Scans & Checkups in India

Antenatal Checkups, Scans and Tests During Pregnancy in India

Regular antenatal care protects both mother and baby. The dates below are typical — your obstetrician will set the exact schedule for you.

Dating or viability scan (weeks 6 to 10): confirms the pregnancy, the heartbeat and your due date.
NT scan and first-trimester screening (11 weeks to 13 weeks 6 days): an early check for chromosomal conditions.
Anomaly or Level II scan (weeks 18 to 22): a detailed check of your baby's organs and growth.
Glucose test (weeks 24 to 28): screens for gestational diabetes, which is more common in South Asian women.
Growth scans in the third trimester: only if your doctor advises them.

Under the government's Pradhan Mantri Surakshit Matritva Abhiyan, pregnant women can get free antenatal check-ups from a doctor at government health facilities on the 9th of every month. Ask at your nearest government hospital or health centre. Your doctor will also advise you on iron, folic acid and calcium supplements and on a balanced diet.

Accuracy

How Accurate Is a Pregnancy Due Date?

Only about 4 to 5 out of every 100 babies are born on their exact due date. A baby born any time between 37 and 42 weeks is considered term, so treat your due date as the middle of a window rather than a deadline.

An ultrasound in the first trimester is generally the most accurate way to date a pregnancy, especially if your cycles are irregular — see the ACOG guidance on estimating the due date and the WHO recommendations on antenatal care. This calculator gives you a quick estimate to start with; your doctor's date always takes priority.

Common Questions

Frequently Asked Questions

What is a pregnancy due date calculator?

A free pregnancy due date calculator estimates your expected date of delivery and how many weeks pregnant you are, using your last menstrual period, conception date or IVF transfer date. It also shows your trimester and key scan dates. It is an estimate, not a diagnosis.

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The most common method is Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period. This calculator also adjusts for your cycle length (a 32-day cycle moves the date 4 days later, a 26-day cycle 2 days earlier) and supports conception date and IVF transfer date.

Doctors count pregnancy from the first day of your last period, not from conception. Enter that date above and the calculator shows your weeks and days, for example 18w 3d means 18 weeks and 3 days. Pregnancy is counted in weeks because it is more precise than months.

A full-term pregnancy is 40 weeks, which is about 9 months and 1 week. Because months have different lengths, doctors use weeks. This calculator groups weeks into 9 pregnancy months, for example month 9 covers weeks 36 to 40. You are already about 2 weeks pregnant at the time of conception.

Yes. Choose Conception date. The due date is 266 days (38 weeks) after conception. Your gestational age still counts 2 weeks earlier, because doctors measure from the last period.

The last-period method can be off by a week or more with irregular cycles. An early ultrasound (dating scan) in the first trimester is more accurate, and your doctor may revise the due date based on it. If your doctor gives you a different date, follow the doctor's date.

Choose IVF transfer date and enter your embryo transfer date. For a Day 5 blastocyst the due date is 261 days after transfer; for a Day 3 embryo it is 263 days. If your clinic has given you a due date, follow the clinic.

Only about 4 to 5 out of every 100 babies are born on the exact due date. Most arrive between 37 and 42 weeks. Treat the due date as the middle of a window, not a deadline.

A typical schedule is a dating or viability scan around weeks 6 to 10, an NT (nuchal translucency) scan at 11 weeks to 13 weeks 6 days, an anomaly (Level II) scan at weeks 18 to 22, and a glucose test for gestational diabetes at weeks 24 to 28. Your obstetrician may plan differently for you.

अपनी आखिरी माहवारी (LMP) के पहले दिन में 280 दिन (40 सप्ताह) जोड़ने पर संभावित डिलीवरी की तारीख मिलती है। ऊपर दिए गए कैलकुलेटर में तारीख डालें — आपको ड्यू डेट, गर्भावस्था का सप्ताह और तिमाही तुरंत मिल जाएगी। यह केवल एक अनुमान है, अपने डॉक्टर से पुष्टि ज़रूर करें।

Last reviewed: May 2026 Based on ACOG & WHO guidance Free — No login required

Results are estimates. Consult a doctor before making health decisions.