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Pregnancy Due Date Calculator
When did it start?
For informational purposes only — not medical advice. Consult a healthcare professional.
Last period ka pehla din - most common method, used by 9 in 10 women.
Twin pregnancy?
Weight gain target adjusts to 16-20kg for twins.
Your due date
Pick the date you know on the left. Your due date, current week and what is happening this week land on this sheet.
How to Calculate Due Date from LMP?
The most widely used method is Naegele's Rule: take the first day of your last menstrual period (LMP), add 7 days, then add 9 months. For example, if your LMP was 15 May 2025: 15 May + 7 days = 22 May 2025, and 22 May 2025 + 9 months = 22 February 2026 - your estimated due date. This assumes a standard 28-day cycle with ovulation around day 14; the calculator above adjusts automatically for longer or shorter cycles.
Pregnancy Week by Week - Baby Size Compared to Fruit
Baby size is usually described using fruit and vegetable comparisons - here it runs from a poppy seed at 4 weeks to a watermelon by full term.
| Week | Fruit | Size | Weight | Trimester |
|---|---|---|---|---|
| 4 | 🌱 Poppy seed - Khus khus | 2mm | 0.5g | 1st |
| 12 | 🍋 Lime - Nimbu | 6cm | 16g | 1st |
| 20 | 🍌 Banana - Kela | 16cm | 300g | 2nd |
| 40 | 🍉 Watermelon - Tarbooz | 35cm | 3.4kg | 3rd |
What Happens in Each Trimester?
1st Trimester (Weeks 1-13)
Morning sickness, thakan, and breast tenderness are common. Folic acid is critical for neural tube development.
Do: start prenatal vitamins, book your first visit. Don't: smoke, drink alcohol, or skip the NT scan.
2nd Trimester (Weeks 14-27)
Often called the "honeymoon period" - energy returns, nausea fades, and quickening (first movement) is felt.
Do: get the anomaly scan (18-20 weeks), start iron/calcium. Don't: skip the glucose tolerance test.
3rd Trimester (Weeks 28-40)
Back pain, swelling, and Braxton Hicks contractions increase. Checkups become more frequent.
Do: track kicks daily, pack your hospital bag by week 35. Don't: ignore reduced baby movement.
How Much Weight Should I Gain in Pregnancy?
For a woman with a normal pre-pregnancy BMI (18.5-24.9), the Institute of Medicine (IOM) recommends a total gain of roughly 11.5-16 kg, though the Indian average tends to run lower at around 10-12 kg. Gain is roughly 1-2 kg in the first trimester, then about 0.4 kg per week through the 2nd and 3rd trimesters. Twin pregnancies typically target 16-20 kg total. These are general guidelines - your doctor will set a target based on your specific pre-pregnancy BMI.
Important Scans in Pregnancy
Three scans matter most in a typical Indian pregnancy: the NT scan (11-13 weeks, ₹1500-3000) screens for chromosomal conditions like Down syndrome; the Anomaly scan / Level 2 USG (18-20 weeks, ₹2000-4000) checks detailed fetal anatomy - heart, brain, limbs, organs; and growth scans (28-32 and 32-34 weeks, ₹1500-2500 each) track baby's growth, position, and fluid levels heading into the third trimester. See the full appointment schedule above once you calculate your due date.
Frequently Asked Questions
How do you calculate the delivery date?
Use Naegele's Rule: add 7 days to your LMP (the first day of your last period), then add 9 months. Or just enter your LMP date into this calculator and the due date is calculated automatically.
How do you calculate due date from LMP?
LMP + 7 days, then + 9 months = your estimated due date. Example: an LMP of March 1 gives an estimated due date of December 8. This is known as Naegele's Rule, used by doctors worldwide.
How big is the baby at 12 weeks?
At 12 weeks, the baby is about 6cm long and 16 grams — roughly the size of a lime. Fingers and toes have separated, and the baby can make a fist.
How much weight should you gain during pregnancy?
For a normal pre-pregnancy BMI, 11-16 kg total is typical — about 1-2 kg in the first trimester, then roughly 0.4 kg per week after that. For twins, the target is 16-20 kg.
Can delivery happen before the due date?
Yes, absolutely. Only about 5% of babies are born on their exact due date. Anywhere from 37-42 weeks is considered "full term" — the due date is only an estimate, not a guarantee.
How do you calculate due date for IVF?
From the embryo transfer date — for a Day 5 blastocyst transfer, the effective LMP is the transfer date minus 19 days. This calculator's IVF tab offers both Day 3 and Day 5 options.
How accurate is an ultrasound due date?
A first-trimester ultrasound (up to 12 weeks) is the most accurate method for estimating due date — typically within +/- 5-7 days. Later ultrasounds are less accurate since babies' growth rates vary individually.
How are pregnancy weeks counted?
Pregnancy weeks are counted from your LMP (the first day of your last period), not from conception — so by the time you actually conceive, you're technically already considered "2 weeks pregnant." It's a bit confusing, but that's the medical standard.
This is for information only, not medical advice. Always consult your gynaecologist. Due date is an estimate - only about 5% of babies deliver exactly on their due date.