Online Pregnancy Due Date Calculator – Free EDD Estimator
Use this online pregnancy due date calculator to estimate your baby's arrival date. Choose from five methods — last menstrual period (LMP), conception date, intercourse date, IVF transfer, or ultrasound. You'll see your estimated due date (EDD), current pregnancy week, trimester, baby's approximate size, conception date, days remaining, a birth probability calendar, and key milestone dates. No sign‑up — all calculations run privately in your browser.
How to Calculate Your Due Date Online for Free
This free online pregnancy due date calculator helps you estimate when your baby will arrive. It uses the same standard obstetric formulas that doctors and midwives use — Naegele's Rule for period‑based calculations and straightforward day‑counting for conception, IVF, and ultrasound methods. Just pick your method, enter a date, and click calculate.
How Each Calculation Method Works
- Last Menstrual Period (LMP). This is the standard OB/GYN method. We add 280 days (40 weeks) to the first day of your last period, then adjust for your cycle length. If your cycle is longer than 28 days, ovulation occurs later and your due date shifts forward. If shorter, ovulation occurs earlier and your due date moves back. This online pregnancy due date calculator from LMP gives you a personalized result.
- Conception Date. A full‑term pregnancy lasts about 266 days (38 weeks) from conception. If you know your exact conception date — for example, from ovulation tracking — we add 266 days. This conception date calculator online is ideal for those who use ovulation predictor kits.
- Intercourse Date. Sperm can live up to 5 days. We estimate conception at roughly 2 days after intercourse, then add 266 days. This intercourse date pregnancy calculator online provides a reasonable window.
- IVF Transfer. The most precise method. For a Day 3 embryo, we add 263 days. For a Day 5 blastocyst, we add 261 days. This IVF due date calculator online reflects the exact embryo age.
- Ultrasound. An early first‑trimester ultrasound is the clinical gold standard. We use the gestational age from your scan report to back‑calculate the due date. This online due date calculator from ultrasound is the most accurate method available.
Why Use This Online Due Date Calculator?
- No registration. A true online pregnancy due date calculator no sign up required. Start immediately — no accounts, no email.
- Five calculation methods. LMP, conception, intercourse, IVF transfer, and ultrasound. This online pregnancy calculator covers every scenario.
- Cycle length adjustment. Unlike calculators that assume a 28‑day cycle, this online pregnancy due date calculator with cycle adjustment lets you enter your actual average cycle.
- Complete pregnancy tracking. See your pregnancy week, trimester, baby's size and weight, estimated conception date, and days remaining.
- Birth probability calendar. Visualize the two‑week window around your due date when most babies arrive.
- Key milestone dates. First heartbeat, end of first trimester, anatomy scan, viability, full term, and more.
- 100% private. All calculations happen in your browser. No personal health data is ever uploaded.
Pregnancy Timeline: Key Milestones
| Milestone | Timing | What Happens |
|---|---|---|
| First Heartbeat | Weeks 6–9 | Baby's heartbeat can be detected via transvaginal ultrasound — one of the most exciting early milestones. |
| End of First Trimester | Week 12 | Risk of miscarriage drops significantly. Many parents feel comfortable sharing their news at this stage. |
| Anatomy Scan | Weeks 18–22 | Mid‑pregnancy ultrasound checks baby's development. Parents can often learn the baby's sex. |
| Viability | Week 24 | Baby has a chance of survival outside the womb with intensive medical care. |
| End of Second Trimester | Week 28 | Third trimester begins. Prenatal check‑ups become more frequent. |
| Full Term | Week 37 | Baby is considered full term. Lungs are mature and ready for life outside the womb. |
| Due Date | Week 40 | Only about 4–5% of babies are born exactly on their due date. Most arrive within two weeks before or after. |
Pregnancy Terms at a Glance
| Term | Weeks | What It Means |
|---|---|---|
| Preterm | Less than 37 weeks | May need extra medical support. |
| Early Term | 37 weeks – 38 weeks, 6 days | Healthy, but final development is still underway. |
| Full Term | 39 weeks – 40 weeks, 6 days | Optimal window for delivery. |
| Late Term | 41 weeks – 41 weeks, 6 days | Monitoring or induction may be discussed. |
| Post‑term | 42 weeks and beyond | Labor might be induced to reduce risks. |
Step‑by‑Step: How to Use the Online Pregnancy Due Date Calculator
- Choose your calculation method. Click one of the five tabs — Last Period, Conception, Intercourse, IVF Transfer, or Ultrasound. LMP is the most common method and is selected by default.
- Enter your details. Fill in the required fields. For LMP, enter the first day of your last period and your average cycle length. For IVF, select whether it was a Day 3 or Day 5 embryo transfer. For ultrasound, enter the gestational age from your scan report.
- Click "Calculate My Due Date". Your estimated due date appears instantly, along with your pregnancy week, trimester, baby's size and weight, conception date, days remaining, birth probability calendar, and key milestone dates.
Frequently Asked Questions
Q: Is this online pregnancy due date calculator really free?
A: Yes, 100% free. No sign‑up, no hidden costs, and no personal data is ever collected. This is a truly free online pregnancy due date calculator — use it as many times as you need.
Q: How accurate is this online due date calculator?
A: Only about 4–5% of babies are born on their exact due date. This calculator uses standard obstetric formulas (Naegele's Rule) and adjusts for cycle length. An early first‑trimester ultrasound is the most accurate dating method. Think of your EDD as the center of your "due window" — it's completely normal to deliver in the two weeks before or after.
Q: Can I use this online calculator if my cycles are irregular?
A: Yes. Enter your best estimate of your average cycle length. For very irregular cycles, doctors often rely on an early ultrasound to set or confirm the due date. This online pregnancy due date calculator for irregular periods provides the best estimate possible with the information you have.
Q: How does cycle length affect my due date?
A: The standard 280‑day calculation assumes ovulation on day 14 of a 28‑day cycle. Longer cycles mean later ovulation, pushing your due date forward. Shorter cycles mean earlier ovulation, moving your due date back. This online pregnancy due date calculator with cycle adjustment handles this automatically.
Q: What is a "full‑term" pregnancy?
A: Full term is 39 weeks, 0 days to 40 weeks, 6 days. Early term is 37–38 weeks, late term is 41 weeks, and post‑term is 42 weeks and beyond. The full‑term window is the optimal time for delivery.
Q: Is my personal data stored or shared?
A: Never. All calculations run locally in your browser. No personal health information — including your last period date, conception date, or IVF transfer date — is ever uploaded, stored, or shared with any server or third party.
Learn how to use this tool correctly by reading our step-by-step tutorial.
