Pregnancy Due Date Calculator
Instantly calculate your estimated due date using LMP, conception date, IVF transfer, or ultrasound — free and medically accurate.
The day bleeding started — not the last day of your period.
Why Calculate Your Due Date?
Pregnancy is an exciting journey, and one of the first questions many parents-to-be ask is “When is my baby due?” Our free pregnancy due date calculator gives you an instant answer. By entering a few simple details — like the first day of your last menstrual period and your average cycle length — our accurate due date calculator applies standard medical rules to compute your estimated due date (EDD).
Knowing your due date helps you plan prenatal care, monitor fetal development, and prepare for the arrival of your little one. It’s fast and easy: just fill in the fields and get your due date in seconds. This estimated due date calculator supports four methods — LMP, conception date, IVF/FET transfer, and ultrasound — so no matter how you track your pregnancy, we have you covered.
How Is Your Due Date Calculated?
Understanding the methods behind pregnancy dating
Last Menstrual Period (LMP) — Naegele's Rule
The most widely used method. Add 280 days (40 weeks) to the first day of your last period. If your cycle differs from 28 days, we adjust the formula: EDD = LMP + 280 + (cycle length − 28). Learn more about Naegele's Rule.
Use this calculator →Conception or Ovulation Date
If you know the exact date you conceived or ovulated, add 266 days (~38 weeks) to get your EDD. This is because pregnancy is dated from the LMP, not conception, so we add 2 weeks fewer than the LMP method.
Use this calculator →IVF / Embryo Transfer
For IVF pregnancies, add 266 days minus the embryo's age. Day 3 transfer: +263 days. Day 5 blastocyst: +261 days. This accounts for the embryo's known developmental stage at the time of transfer.
Use this calculator →Ultrasound (CRL Dating)
Early ultrasound before 13 weeks is often the most accurate dating method. Using the crown-rump length (CRL) or gestational age from your scan: EDD = Scan Date + (280 − GA in days). Ultrasound is especially useful for irregular cycles.
Use this calculator →How Accurate Is a Due Date?
What every expecting parent should know
Keep in mind that a due date is only an estimate. Most pregnancies last around 40 weeks, but full-term pregnancy is officially 37 weeks 0 days to 40 weeks 6 days. A baby born one week before or after the calculated due date is still considered full term.
Obstetricians consider delivery anywhere from 37 to 42 weeks as normal. If labor doesn’t start by 42 weeks, your healthcare provider will monitor you closely and discuss options. Use your due date as a planning tool — not a guarantee. Learn more about due date accuracy →
Pregnancy Week by Week
Detailed baby development, symptoms, and tips for all 42 weeks
Explore by Trimester
Organ formation, morning sickness, and your first OB visits. The most critical period of development.
The 'golden period' — energy returns, bump grows, baby movements begin, anatomy scan.
Final preparations. Baby gains weight rapidly, birth plan discussions, and nesting instinct kicks in.
Why Use Our Pregnancy Due Date Calculator?
Trusted by expecting parents around the world
Fast & Easy
Enter your LMP and cycle length — get your due date in under 3 seconds. No forms, no sign-ups.
Medically Accurate
Uses Naegele's Rule and IVF/FET protocols — the same methods used by OB/GYNs worldwide.
Full Pregnancy Dashboard
See your trimester, milestones, baby development, and planning dates — not just a single date.
Customizable
Handles irregular cycles, IVF, FET, conception dates, and ultrasound CRL measurements.
Free & Private
No cost, no sign-up, no data stored. All calculations happen locally in your browser.
Works Everywhere
Fully optimized for phones, tablets, and desktops. Calculate your due date from anywhere.
More Pregnancy & Due Date Calculators
Frequently Asked Questions
Common questions answered by our medical team