Pregnancy Week Calculator – Track Your Week of Pregnancy
This Pregnancy Week Calculator helps you find how many weeks pregnant you are based on your last menstrual period (LMP). It also shows your estimated due date and which trimester you are in, so you can follow doctor advice, baby growth charts, and appointment schedules more confidently.
Enter Your Last Period Date (LMP)
Note: This calculator is for information only and does not replace a doctor’s advice or ultrasound.
Result
Method Used
- Gestational age = Today − LMP (in days) → converted to weeks + days.
- Estimated due date (EDD) = LMP + 280 days (40 weeks).
- Trimester is based on your pregnancy week (1st, 2nd, or 3rd).
- All values are approximate and for general guidance only.
Important Notes
- Works best if you remember the first day of your last menstrual period (LMP).
- Assumes a standard 28-day menstrual cycle and 40-week pregnancy.
- Actual due date and pregnancy week may change after doctor check-up or ultrasound.
- Always consult your gynecologist for medical decisions and health advice.
How Does the Pregnancy Week Calculator Work?
This pregnancy week calculator uses the most common medical method: it counts pregnancy from the first day of your last menstrual period (LMP), not from the day of conception. This is the same method most doctors and hospitals follow when they talk about “weeks pregnant”.
1. You enter your LMP date
Type the first day of your last menstrual period in the date box. If you are not sure, use the date your doctor wrote on your prescription or report.
2. The tool counts days and weeks
The calculator finds how many days have passed between your LMP and today. It then converts this into full weeks and extra days (for example: 18 weeks 4 days).
3. Due date is estimated
Your estimated due date (EDD) is calculated by adding 280 days (40 weeks) to your LMP date. This is only an estimate; babies can arrive a little earlier or later.
4. Trimester is shown
Based on your weeks of pregnancy, the calculator shows whether you are in your 1st, 2nd, or 3rd trimester. This helps you read pregnancy articles and checklists made for your current stage.
Important health disclaimer
This tool is for learning and planning only. It cannot confirm pregnancy or replace ultrasound, blood tests, or any medical check-up. Always talk to your doctor for any health decision.
Where Can You Use This Pregnancy Week Calculator?
You can use this pregnancy week calculator whenever you want to quickly check how many weeks pregnant you are and what that means for your day-to-day planning. Here are some common and helpful uses.
Preparing for doctor visits
Know your exact pregnancy week before check-ups so you can tell the doctor clearly and understand advice for your current stage.
Tracking baby’s growth
Match your pregnancy week with baby growth charts, weekly articles, and mobile apps that show what is happening inside the womb.
Diet & lifestyle changes
Use your trimester and week to follow the right nutrition, exercise, and rest guidelines shared by your doctor or nutritionist.
Planning maternity leave
Check how many weeks are left until your due date to plan office work, handover, and maternity leave applications properly.
Hospital bag & home setup
Use your week count to decide when to pack your hospital bag, arrange baby clothes, crib, and other essentials at home.
Family bonding & celebrations
Share your pregnancy week with family, track milestones like entering a new trimester, and plan photos or small celebrations.
Pregnancy Week Calculator – FAQ
It uses the first day of your last menstrual period (LMP) and counts forward in weeks and days to estimate how pregnant you are today.
Most doctors and hospitals also count pregnancy weeks from the LMP date, so this method is a common standard in maternity care.
No. It is only an educational tool. Pregnancy confirmation, due date changes, and medical advice must come from your doctor and ultrasound reports.
You can use your best memory or check old notes, pads, or apps. But for accurate dating, ask your gynecologist to guide you using scans and tests.
Doctors may adjust your due date based on ultrasound measurements and your cycle length. In that case, always follow your doctor’s calculation.
Yes. The pregnancy week calculator on Skjee is completely free to use on mobile, tablet, and desktop for unlimited calculations.
