How to Use the Pregnancy & Due Date Calculator
This calculator is designed to provide immediate answers without manual arithmetic or confusing steps. Simply input your values into the fields above; results update automatically as you adjust numbers. You can also customize your currency and tax preferences using the region selector in the header.
Formula & Calculation Method
Naegele's Rule: Estimated Due Date = First day of LMP + 1 year - 3 months + 7 days (280 days)
Our algorithms strictly follow standard international accounting, scientific, and engineering formulas to ensure 100% precision.
Frequently Asked Questions
How accurate is the estimated due date?
Only about 4% to 5% of babies are born on their exact due date, but roughly 80% arrive within two weeks before or after.
How are the three trimesters defined?
First trimester: Weeks 1-12; Second trimester: Weeks 13-26; Third trimester: Week 27 through delivery.