Use this pregnancy due date calculator to estimate your expected delivery date, pregnancy week, and trimester stage. It works with both LMP (last menstrual period) and conception date, giving you fast, medically guided results that align with standard obstetric methods used worldwide.
Pregnancy Due Date Calculator Based on Conception & Period | Free Tool Mart
Pregnancy Due Date Calculator
Estimated Delivery Date (EDD)
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How far along
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Current Trimester
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| Milestone | Date |
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This calculator provides general estimates only and does not replace professional medical advice, diagnosis, or care. Always discuss your dates and pregnancy with your healthcare provider.
How to Use the Pregnancy Due Date Calculator
Enter Your Last Period or Conception Date
Start by entering either the first day of your last menstrual period or your conception date. The calculator uses these inputs to determine your pregnancy week and estimate your due date.
Add Cycle Length (If Not 28 Days)
If your menstrual cycle is longer or shorter than the common 28-day cycle, enter your average length. The period pregnancy calculator adjusts ovulation timing automatically for more accurate results.
Click “Calculate Due Date”
You instantly receive:
Your estimated due date (EDD)
Current pregnancy week
Trimester stage
How far along you are today
It also works as a pregnancy week calculator by LMP and a pregnancy week calculator by due date.
Pregnancy Due Date Calculator – Free Tool Mart
This pregnancy calculator uses three clinically recognized methods to give precise estimates:
- LMP-based due date
- Conception-based due date
- IVF / embryo transfer-based due date
You can quickly check:
- Expected Date of Delivery (EDD)
- Gestational age
- Trimester stage
- Week-by-week pregnancy progress
Whether you search “calculate my due date”, “pregnancy week calculator”, or “pregnancy calculator by due date”, this tool provides clear results instantly.
How Does the Pregnancy Due Date Calculator Work?
This calculator follows standard formulas used by obstetricians and gynecologists across the world. It supports due dates based on LMP, conception, IVF, and ultrasound adjustments.
1. LMP Due Date Method
The most commonly used approach in clinics.
Formula:
EDD = LMP + 280 days (40 weeks)
Use this if you clearly remember your last menstrual period. This method also helps calculate gestational age and pregnancy weeks using LMP.
2. Conception Date Method
Best suited if you track your ovulation or know your exact conception date.
Formula:
EDD = Conception Date + 266 days (38 weeks)
This method often gives a very precise estimate because it starts from actual fertilization timing.
3. IVF / Fertility Treatment Method
IVF pregnancies follow specific rules based on embryo age:
- Day-3 embryo transfer → add 263 days
- Day-5 embryo transfer → add 261 days
This gives a highly accurate IVF due date because the fertilization and implantation timeline is known.
4. Ultrasound Measurement Method
Early ultrasound, especially in the first trimester, can adjust your due date based on the CRL (crown-rump length).
Your doctor may revise the expected delivery date if ultrasound measurements differ from your LMP values.
Accuracy of the Due Date
Most babies arrive between 38 and 42 weeks.
This tool follows global medical standards and provides:
- A reliable EDD estimate
- Pregnancy weeks
- Trimester position
However, medical evaluation always finalizes the due date.
Why Use Our Pregnancy Due Date Calculator?
Medically Trusted & Accurate
Uses OB-GYN–approved formulas for LMP, conception, irregular cycle lengths, and IVF transfers.
Clear Pregnancy Tracking
Use the calculator to see:
- How many weeks pregnant you are
- Your trimester
- Your due date window
- Your pregnancy timeline
100% Free & Mobile Friendly
Works instantly on desktop, tablet, and mobile without sign-ups or app downloads.
FAQs – Pregnancy Due Date Calculator
It’s a tool that estimates your expected date of delivery (EDD) using your LMP or conception date. It also functions as a pregnancy week calculator, showing current gestational age, trimester, and how far along you are.
Your doctor may later adjust this based on ultrasound results.
Due dates are estimates. Only about 5% of babies are born on the exact date. Most deliveries occur between 38 and 42 weeks.
The calculator follows standard medical formulas, but your doctor may update the due date after early ultrasounds.
It uses two globally accepted formulas:
- LMP Method: LMP + 280 days
- Conception Method: Conception Date + 266 days
If your cycle is irregular, the calculator adjusts ovulation timing, making it a reliable period pregnancy calculator.
Yes. Enter your average cycle length.
The tool adjusts your LMP-based ovulation estimate, giving you a more accurate EDD.
IVF uses fixed embryo-age rules:
- Day-3 embryo transfer: add 263 days
- Day-5 embryo transfer: add 261 days
This eliminates uncertainty about ovulation or implantation timing.
Just one:
- LMP date
or - Conception date
Optionally:
- Cycle length
- IVF transfer details
The calculator then shows your pregnancy week, trimester, and due date.
Doctors often rely on ultrasound (CRL) in the first trimester.
If ultrasound and LMP don’t match, doctors adjust the EDD — this is medically normal.
Yes. It works even if you are:
- 5 weeks
- 12 weeks
- 30 weeks
- 35+ weeks
It acts as a:
- Pregnancy week calculator by due date
- How many weeks pregnant am I tool
- Gestational age calculator
It’s medically informed but not a substitute for prenatal care. Always follow professional medical advice.
No tool can predict the exact day.
It provides your estimated delivery window, helping with planning and pregnancy tracking.
Yes.
If you already know your EDD, the calculator works backward to show your exact pregnancy week.
Yes.
If you know when you conceived, this is one of the most accurate approaches because it bypasses cycle-length variations.
Learn More About Pregnancy and Due Dates
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