Wondering exactly when your little one will arrive? The wait can feel endless, especially when you’re tracking every symptom and planning for the big day. A Due Date Calculator takes the guesswork out by using your last menstrual period (LMP), conception date, or ultrasound data to predict your estimated due date (EDD).
Our clinically accurate tool follows standard obstetric guidelines so you can plan prenatal visits, prepare your nursery, and track your 40-week pregnancy with confidence. Try the Due Date Calculator below to get instant results.
🩺 Medically Accurate
Due Date CalculatorEstimate your baby's arrival with clinically verified methods
Must be within the last 10 months
Normal range: 21–45 days
Typically 14 days after period start
Most reliable: first trimester scans (6–13 weeks)
Estimated Due Date
Gestational Age
Trimester
Days Remaining
Progress
ConceptionTodayDue Date
T1
T2
1st Trimester
Weeks 1–132nd Trimester
Weeks 14–273rd Trimester
Weeks 28–40
Weeks 1–132nd Trimester
Weeks 14–273rd Trimester
Weeks 28–40
Pregnancy Milestones
⚕️ Medical Disclaimer: This calculator uses Naegele's Rule and standard obstetric guidelines. Results are estimates only. Always consult your healthcare provider for accurate pregnancy dating and prenatal care.
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What Is a Due Date Calculator?
A Due Date Calculator estimates your baby’s expected delivery date based on key pregnancy dates. It primarily uses the first day of your last menstrual period (LMP), since most people don’t know the exact date of conception. The standard pregnancy lasts about 40 weeks (280 days) from LMP.
This tool applies Naegele’s rule and other verified methods to calculate gestational age from LMP, predict your estimated due date, and show your current trimester and progress. It also outlines important pregnancy milestones so you know what to expect week by week. Healthcare professionals and expecting parents alike rely on these calculators for quick, reliable estimates that support better prenatal planning.
How to Use the Due Date Calculator
Using the tool is straightforward. Follow these simple steps:
- Choose your calculation method — Select Last Period (LMP Method) for most accurate results with regular cycles, Conception if you know the ovulation or conception date, or Ultrasound for scan-based dating.
- Enter the first day of your last menstrual period (or the relevant date based on your chosen method). The tool accepts dates within the last 10 months.
- Adjust your average cycle length — The default is 28 days, but you can change it to match your typical cycle (normal range: 21–45 days).
- Click “Calculate Due Date” — The tool instantly computes your results using standard methods.
You’ll receive your estimated due date, gestational age (e.g., 29 weeks 1 day), current trimester, days remaining, pregnancy progress percentage, and a full timeline of milestones. Use this information to discuss with your doctor or track your pregnancy calendar.
Why Use a Due Date Calculator?
- Accurate pregnancy planning — Knowing your EDD helps schedule prenatal appointments, tests, and maternity leave precisely.
- Track gestational age from LMP — See exactly how far along you are and what developments are happening each week.
- Reduce anxiety with clear milestones — Get a visual timeline of key events like heartbeat detection, anatomy scans, and viability.
- Support for different scenarios — Whether you have a regular cycle, know your conception date, or have ultrasound data, the tool adapts for reliable estimates.
- Free and instant access — No downloads or sign-ups needed — perfect for couples planning pregnancy or busy parents-to-be.
- Educational insights — Understand your pregnancy timeline and prepare emotionally and practically for each stage.
Due Date Calculation Explained: Key Concepts
The most common method is Naegele’s rule: Add 1 year to the LMP, subtract 3 months, and add 7 days. This assumes a 28-day cycle with ovulation around day 14, leading to a 280-day (40-week) pregnancy.
For example, if your LMP started on September 27, 2025, the calculator would estimate your due date around July 4, 2026. It also accounts for cycle-length variations and offers conception or ultrasound options for greater precision.
Gestational age from LMP counts the full pregnancy from the first day of your period, even though actual conception usually happens about 2 weeks later. This standardized approach helps doctors monitor growth consistently. Real-world example: A couple using the LMP method discovered their baby was in the third trimester earlier than expected, allowing them to prepare the nursery and attend extra check-ups. Always remember these are estimates — only about 5% of babies arrive exactly on the due date.
Frequently Asked Questions
Select your preferred method (LMP, Conception, or Ultrasound), enter the required date and cycle length if needed, then click Calculate. You'll instantly see your estimated delivery date, gestational age, and full pregnancy milestones. It's designed to be simple for anyone tracking their pregnancy due date.
? Enter the first day of your last menstrual period into an LMP due date calculator. The tool adds 280 days (or applies Naegele's rule) to provide your EDD. Adjust for cycle length if yours differs from 28 days for better accuracy.
Early ultrasound dating is often the most precise, especially in the first trimester. LMP works well for regular cycles, while conception date is useful if known. Combine methods and always confirm with your healthcare provider.
These tools provide strong estimates based on standard guidelines, but only about 5% of babies are born on their exact due date. They offer a reliable window (typically ±2 weeks) and help track progress effectively.
Yes. If you know your conception or ovulation date, select that method. Add about 266 days (38 weeks) to the conception date for your estimated delivery date. This can be more precise for those tracking cycles closely.
A Due Date Calculator gives you clarity and confidence during one of life’s most exciting journeys by delivering quick, accurate estimates of your baby’s arrival. Whether you’re using it for LMP due date tracking or milestone planning, it simplifies your pregnancy timeline.
Ready to find out when your baby is due? Try the Due Date Calculator now and start preparing for those precious first moments.
Last Update: April 2026