Due Date Calculator - Pregnancy Due Date Estimate Online
Calculate your pregnancy due date from your last menstrual period (LMP) or conception date. See key pregnancy milestones by trimester.
How to use this calculator
👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉
In plain English — what does this do?
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A due date calculator estimates when a baby is expected to be born based on the first day of the last menstrual period (LMP), a known conception date, or an IVF transfer date. A full-term pregnancy lasts approximately 40 weeks (280 days) from the LMP. The result is an estimated due date — most babies arrive within two weeks of this date.
Estimated Due Date
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Key milestones
This calculator provides estimates only. Consult a healthcare provider for medical confirmation.
What is Due Date Calculator - Pregnancy Due Date Estimate Online?
A due date calculator estimates when a baby is expected to be born based on the first day of the last menstrual period (LMP), a known conception date, or an IVF transfer date. A full-term pregnancy lasts approximately 40 weeks (280 days) from the LMP. The result is an estimated due date — most babies arrive within two weeks of this date.
How to use it
- 1️⃣ Choose your input method: last menstrual period, conception date, or IVF transfer date.
- 2️⃣ Enter the relevant date using the date picker.
- 3️⃣ If using LMP, enter your cycle length — the default is 28 days.
- 4️⃣ The calculator displays your estimated due date and current week of pregnancy.
- 5️⃣ Review the key milestones table to see trimester boundaries, viability week, and full-term date.
💡 See it in action — a real example
❓ Common questions
- How accurate is an estimated due date?
- Only about 5% of babies are born on their exact due date. Most arrive within 1 to 2 weeks before or after. The due date is best understood as the midpoint of a normal delivery window rather than a precise target.
- What if my cycle is not 28 days?
- Enter your actual cycle length in the cycle length field. The calculator adjusts the estimated ovulation day and due date accordingly. Shorter cycles shift the due date earlier; longer cycles shift it later.
- Can I use conception date instead of LMP?
- Yes. Switch to the Conception Date tab and enter when you believe conception occurred. This is particularly useful if you tracked ovulation and know the approximate date.
- How does IVF dating work?
- For IVF transfers, the calculator adds a fixed number of days to the transfer date based on embryo age. A Day 5 blastocyst transfer is treated as if conception occurred 17 days before the transfer date.
- When should I see a doctor to confirm my due date?
- An early ultrasound, typically at 8 to 12 weeks, is the most accurate way to confirm gestational age and due date. Always consult a healthcare provider for medical confirmation of your pregnancy timeline.