Estimate Your Baby's Due Date
How Each Method Works
🩸 Last Period
Standard method: 280 days from the first day of your last period, adjusted for your average cycle length.
🌸 Conception Date
266 days from the actual day of conception (ovulation), since conception itself doesn't need the cycle-length adjustment.
🔬 Ultrasound Date
Counts back from the gestational age measured at your dating scan — the most reliable method if your periods are irregular.
🧬 IVF Transfer Date
Counts forward from the exact known age of the embryo — 263 days for a Day-3 transfer, or 261 days for a Day-5 (blastocyst) transfer.
Due Date FAQs
Only about 5% of babies arrive on their exact calculated due date. It's a useful estimate — most babies arrive within 1-2 weeks before or after this date. Your doctor will refine it further using ultrasound measurements.
In IVF, the embryo's exact age is known at transfer, so doctors count forward from that precise age rather than estimating from a last period date. A Day-5 (blastocyst) transfer uses a shorter count than a Day-3 transfer because the embryo is already 2 days more developed.
Yes, especially if periods are irregular or the exact last period date is uncertain. A first-trimester dating scan (typically 8-13 weeks) is considered the most reliable single measurement for confirming due date.
No. This tool only estimates a due date assuming pregnancy is already confirmed. For confirming pregnancy itself, a blood or urine hCG test and ultrasound are needed — available at Diwya Vatsalya Mamta, Patna.
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