Gestational Week Calculator
Pregnancy is a journey filled with anticipation and important milestones. Knowing your gestational age—how far along you are in your pregnancy—is essential for monitoring fetal development, scheduling check-ups, and preparing for delivery. The Gestational Week Calculator is a versatile tool designed to help expectant mothers, healthcare providers, and families calculate the current week of pregnancy using various medically accepted methods.
Whether you want to calculate based on your Last Menstrual Period (LMP), the exact conception date, an estimated due date, or measurements from an ultrasound scan, this calculator provides accurate and easy-to-understand results. It helps you stay informed about your pregnancy progress, including how many days pregnant you are, the estimated due date, and the current trimester.
How to Use the Gestational Week Calculator
Step 1: Select Calculation Method
Choose one of the following methods depending on your available information:
- Last Menstrual Period (LMP): Common method based on the first day of your last period.
- Conception Date: Based on the estimated or known date of fertilization.
- Due Date: Calculate backward from your estimated due date.
- Ultrasound Dating: Use the ultrasound date and gestational age measured at that time.
Step 2: Input Required Data
Depending on your method choice, fill in the relevant date(s):
- For LMP, enter the first day of your last menstrual period.
- For Conception Date, enter the estimated date of conception.
- For Due Date, enter your estimated delivery date.
- For Ultrasound, enter the ultrasound date and the gestational age (in weeks) at that ultrasound.
Step 3: Calculate
Click the Calculate button to get your gestational age, due date, days pregnant, trimester, days until due date, and estimated conception date.
Step 4: View Results
Your pregnancy details will be displayed clearly, helping you understand your progress and plan accordingly.
Example Use Case
Suppose you know the first day of your last menstrual period was January 1, 2026, and today’s date is January 30, 2026.
- Select Last Menstrual Period method.
- Input January 1, 2026 in the LMP field.
- Click Calculate.
The calculator will show:
- Gestational Age: 4 weeks, 1 day
- Due Date: October 8, 2026 (280 days from LMP)
- Days Pregnant: 30 days
- Trimester: First Trimester (1-12 weeks)
- Days Until Due: 252 days
- Estimated Conception Date: January 15, 2026
Why Use This Calculator?
- Multiple Calculation Methods: Use the one best suited to your information.
- Accurate Pregnancy Tracking: Helps monitor fetal development stages.
- Easy to Use: Simple interface with date pickers and clear results.
- Educational: Understand pregnancy milestones like trimesters and due dates.
- Helpful for Planning: Know how far along you are and when to expect delivery.
Frequently Asked Questions (FAQs)
1. What is gestational age?
Gestational age is the age of your pregnancy measured in weeks and days from the start of your last menstrual period.
2. Why are there different calculation methods?
Different methods suit various scenarios. LMP is standard, but conception date, due date, or ultrasound measurements provide alternatives if LMP is unknown or unreliable.
3. How accurate is the due date?
Due dates are estimates based on average pregnancy length; actual delivery can vary by up to two weeks before or after.
4. What is the difference between conception date and LMP?
Conception typically occurs about two weeks after the first day of LMP.
5. How is trimester determined?
Pregnancy is divided into three trimesters: 1-12 weeks, 13-26 weeks, and 27-40 weeks.
6. Can I use this calculator if I only know my due date?
Yes, enter the due date, and the calculator will estimate your current gestational age.
7. How does ultrasound dating work?
Ultrasound dating uses measurements of the fetus to estimate gestational age, useful if LMP is unknown or irregular.
8. What if I am past my due date?
The calculator shows how many days overdue you are.
9. Can this calculator be used for multiple pregnancies?
Yes, gestational age calculation is the same regardless of single or multiple pregnancies.
10. Does the calculator account for irregular cycles?
It assumes a standard 28-day cycle; for irregular cycles, consult your healthcare provider.
11. Can I calculate gestational age for past dates?
Yes, enter past dates to find gestational age on any specific date.
12. How is the conception date estimated?
Typically, conception is estimated as 14 days after LMP.
13. What does “days pregnant” mean?
It counts the total number of days since the start of pregnancy.
14. Is the trimester classification universal?
Yes, the three trimesters are a globally accepted pregnancy division.
15. Can I reset and enter new data?
Yes, use the reset button to clear inputs and start a new calculation.