Pregnancy Due Date Calculator – LMP Based
Use this Pregnancy Due Date Calculator to estimate your due date, current pregnancy week, trimester, conception window, and key milestones based on your last menstrual period (LMP) and usual cycle length.
Enter Your Details
Estimate only. Consult your healthcare provider for clinical dating.
Method & Adjustments
- Naegele’s Rule: Due Date = LMP + 280 days
- Cycle Adjust: Due Date += (Cycle − 28) days
- Gestational Age Today = Today − LMP (in weeks & days)
- Conception Window ≈ LMP + (Cycle − 14) ± 1 day
Key Milestones
- End of 1st Trimester (≈13w0d): –
- Start of 3rd Trimester (≈28w0d): –
- Full Term (37w0d): –
- Due Date (40w0d): –
Where Can You Use This Pregnancy Due Date Calculator?
You can use this Pregnancy Due Date Calculator in many real-life situations to plan checkups, work, and family life around your expected due date.
Planning Doctor Visits & Scans
Use your estimated due date to schedule regular checkups, ultrasound scans, and tests at the right pregnancy weeks.
Maternity Leave & Work Planning
Plan when to start maternity leave, hand over office work, and manage workload before your third trimester.
Hospital Bag & Birth Prep
Prepare your hospital bag, choose a hospital, and discuss birth plans with your doctor based on the expected due date.
Baby Shopping & Budget Planning
Decide when to buy baby clothes, cradle, diapers, and other essentials without rushing at the last moment.
Family Events & Travel Plans
Avoid long trips close to your due date and plan family functions or visits safely during the second trimester.
Tracking Weekly Pregnancy Milestones
Follow your baby’s growth week-by-week, and know when each trimester starts and important milestones happen.
Pregnancy Due Date Calculator – FAQ
It uses Naegele’s rule based on the first day of your last menstrual period (LMP), adds 280 days (40 weeks), and adjusts for your usual cycle length to estimate your due date.
Enter the first day of your last menstrual period (LMP) and your average cycle length. The calculator uses these to estimate your due date and current pregnancy week.
You can change the cycle length field. The tool adjusts your due date by the difference from 28 days, so longer cycles push the date forward and shorter cycles pull it back slightly.
It gives an estimated due date based on standard rules. Many babies arrive between 37 and 42 weeks, so your doctor and ultrasound reports are more accurate for medical decisions.
You can still get a rough idea, but IVF and some fertility treatments use specific embryo transfer or conception dates. Always follow the due date given by your fertility clinic or doctor.
No. This calculator is for educational and planning purposes only. For any health concerns, high-risk pregnancy, or exact dating, please consult your doctor or midwife.
