Pregnancy Calculator: Find Your Due Date, Week & Trimester
Curious about how many weeks pregnant you are or when your baby will arrive? Use our free pregnancy calculator to estimate your due date, pregnancy week, trimester, and gestational age in minutes. The Pregnancy Calculator has been reviewed by Swapnil Kaushik (Certified Childbirth Educator-International) and trusted by pregnant women throughout India. Enter your LMP, conception date or IVF transfer date in the calculator to begin.
Reviewed bySwapnil KaushikCertified Childbirth Educator
Due Date Calculator
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Likely arrival window
Current Pregnancy Week
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Key dates & milestones
What Is a Pregnancy Calculator?
A pregnancy calculator estimates your due date (EDD), how far along you are in weeks, and your gestational age based on either the first day of your last menstrual period (LMP), the date you conceived or a fertility treatment date. It uses Naegele's Rule, which is the same method your doctor will use to calculate your due date. This method adds 280 days (or 40 weeks) to the first day of your LMP.
Keep in mind that due dates are just an estimate. Only 5% of babies will actually be born on their due date. Most babies are born between two weeks early and two weeks late.
Naegele's Rule
5%
of babies are born on their exact due date.
Most babies arrive in the four weeks around the due date.
How to Calculate Your Pregnancy Due Date
There are four common ways to estimate your due date:
1. By Last Menstrual Period (LMP)
The most common method. Count 280 days (40 weeks) from the first day of your last period. This assumes a standard 28-day cycle — if your cycle is longer or shorter, your due date shifts accordingly.
2. By Conception Date
If you know your exact conception date, your due date is roughly 266 days later. This method tends to be more accurate than LMP-based calculation, especially for women with irregular cycles.
3. By IVF Transfer Date
For pregnancies conceived through IVF: count 263 days from a Day 3 embryo transfer, or 261 days from a Day 5 transfer, to estimate your due date.
4. By Ultrasound Scan
A first trimester ultrasound or early dating ultrasound measures the crown-rump length of your baby. Sometimes an ultrasound provides a more accurate due date than LMP dating. This is especially true if your cycles aren't regular.
Understanding Your Pregnancy Week & Trimester
Pregnancy is medically tracked in weeks, not months, which is why your calculator result may feel different from a simple "9-month" estimate. Here's how the 40 weeks break down:
| Trimester | Weeks | Months |
|---|---|---|
| First Trimester | Week 1–13 | Month 1–3 |
| Second Trimester | Week 14–27 | Month 4–6 |
| Third Trimester | Week 28–40 | Month 7–9 |
What Is Gestational Age?
Gestational age is the period of time measured in weeks from the first day of your LMP. Remember that this is not calculated from the date of conception, which happens about two weeks after your LMP. Your obstetrician reports your baby's age in gestational age (rather than "fetal age") on all prenatal reports, ultrasounds, and hospital records. Therefore, it's the age you'll see most often.
Gestational age vs. fetal age
Gestational age · counted from your LMP
Fetal age · counted from conception
Example: at a 12-week scan, your baby's fetal age is about 10 weeks.
Ovulation & Conception Calculator
Trying to understand your fertile window or confirm a possible conception date? Our calculator also estimates:
Your most fertile days (ovulation window)
Estimated implantation date
Estimated conception date (if working backward from a known due date)
This is especially useful if you're in the pre-conception phase — explore our Pre-Conception & Fertility Yoga Classes →
Example: a 28-day cycle
- Period · days 1–5
- Fertile window · days 9–14
- Ovulation · around day 14
- Implantation · 6–12 days after ovulation
- Pregnancy test · from day 29, your missed period
Pregnancy Calculator for Indian Mothers
Our pregnancy calculator is designed keeping expecting mothers from India in mind. The results are displayed in English, Hindi, Marathi and Tamil. Track your pregnancy from Delhi NCR, Gurugram, Mumbai or any place else in India with this free tool. Get instant access to your medically-reviewed estimated results - no app download needed.
- 4 languages
- Expert-reviewed
- No app download
Frequently Asked Questions
Quick answers about due dates, gestational age and pregnancy tests.
Book a ConsultationEnter the first day of your last menstrual period into the calculator above, and it will instantly show your current week, based on the number of days since your LMP.
Gestational age is counted in weeks from the first day of your last menstrual period, not your conception date, which is why it's typically about two weeks "ahead" of your baby's actual age.
Your conception date is when the egg was fertilized (usually mid-cycle). Your due date is estimated as 280 days from your LMP, or about 266 days from your actual conception date.
It provides a reliable estimate, but only around 5% of babies are born on their exact due date. Most healthy pregnancies deliver anywhere between 37 and 42 weeks.
Yes. Your doctor may adjust your due date based on your first-trimester ultrasound, especially if your cycles are irregular or the ultrasound measurements suggest a different gestational age than your LMP-based estimate.
Many physicians advise waiting until the first day of your missed period for the most accurate result. You can also use our calculator to determine the earliest date you can expect an accurate test result based on your cycle.
Why Track Your Pregnancy With Us
Our calculator is different from other due-date tools. It's developed by Mrs. Swapnil Kaushik, an internationally certified childbirth educator with 10+ years of experience who has worked with 15,000+ mothers.
- 10+Years of experience
- 15,000+Mothers supported
After finding out your due date and trimester, find out what's next:
Disclaimer: This pregnancy calculator should be used for estimating purposes only. You should always consult with your gynaecologist/obstetrician to verify your due date and manage your pregnancy.