Pregnancy Due Date Calculator
Estimate a pregnancy due date, current week, and trimester from the first day of the last period.
Enter the first day of your last period to estimate your due date.
Based on a standard 280-day estimate from a 28-day cycle — an approximation only. Your healthcare provider's estimate, especially if based on an ultrasound, is more accurate for your specific situation.
Overview
A standard estimate of due date, current week of pregnancy, and trimester based on the widely used 280-day calculation.
- Shows current week and day, not just the due date
- Identifies the current trimester
- Instant results from a single date
How to use it
- 1Enter the first day of your last period
- 2Read your estimated due date and current progress
Frequently asked questions
How is the due date calculated?
Using Naegele's rule — adding 280 days (40 weeks) to the first day of the last menstrual period, assuming a standard 28-day cycle.
Is this a substitute for a doctor's estimate?
No — this is a general estimate. An ultrasound-based estimate from a healthcare provider is more accurate for your specific pregnancy, especially if your cycle isn't a typical 28 days.