Pregnancy Due Date Calculator
Last Menstrual Period
How It Works
- LMP: Uses Naegele's Rule (LMP + 280 days). Cycle length adjusts ovulation.
- Conception: Due date = conception + 266 days.
- Ultrasound: Derives LMP from ultrasound date and GA, then calculates EDD.
- IVF: Adjusts embryo age to conception equivalent, then calculates EDD.
Overview
Use this pregnancy due date calculator to estimate your expected due date, current gestational age, trimester, and pregnancy milestones using the most common dating methods. It supports last menstrual period, conception date, ultrasound dating, and IVF transfer timing, which makes it more useful than a simple single-input due date estimate. This page is designed to help you understand pregnancy timing clearly while keeping the result private and easy to review.
About
About Pregnancy Due Date Estimation
Pregnancy dating is usually an estimate built from the best available timing information. Different methods are useful in different situations, so this tool supports the common calculation paths clinicians and patients reference most often.
Features:
- LMP-based due date estimation using Naegele's Rule
- Conception-date calculation for known conception timing
- Ultrasound-based dating support
- IVF and embryo-transfer due date support
- Gestational age, trimester, and milestone tracking
- Private browser-based calculation with printable results
Which dating method is usually best?
If you have a reliable LMP, that is often the first estimate people use. If cycle timing was unusual or uncertain, an early ultrasound is often considered more accurate. For assisted reproduction, IVF transfer details usually provide the clearest timeline because the embryo age is known more precisely.
FAQ
What does this calculator estimate besides the due date?
It also helps you see gestational age, trimester timing, important milestones, and the full-term window so the result is more useful for planning.
Why can different methods give slightly different due dates?
They use different timing assumptions. LMP relies on cycle timing, ultrasound relies on fetal measurement-based dating, and IVF uses known transfer timing, so the estimates can vary a bit.
Is ultrasound dating usually more accurate than LMP?
Early ultrasound is often the most precise dating method when cycle timing is uncertain, especially in the first trimester.
Does this replace advice from a doctor or midwife?
No. It is a planning and estimation tool. Clinical dating and prenatal guidance should still come from your healthcare provider.