🤰 Pregnancy Due Date Calculator
Calculate your estimated due date from last menstrual period, conception date, or IVF transfer date. Track your current week and trimester.
Estimated Due Date
Pregnancy Due Date Calculator
This calculator estimates your due date using three different methods. The most common method uses the first day of your last menstrual period (LMP) and adds 280 days (40 weeks). You can also calculate from a known conception date or an IVF transfer date.
How It Works
- LMP method: Adds 280 days (Naegele's rule)
- Conception: Adds 266 days (38 weeks of gestation)
- IVF 5-day transfer: Adds 261 days (266 − 5)
- IVF 3-day transfer: Adds 263 days (266 − 3)
Frequently Asked Questions
How accurate is a due date calculator?
A due date calculator based on the last menstrual period is accurate to within about 5 days for women with regular 28-day cycles. Ultrasound dating in the first trimester is more accurate (within 3–5 days). Only about 5% of babies are born exactly on their due date.
What is the 280-day rule?
The 280-day rule (or Naegele's rule) estimates the due date by adding 280 days (40 weeks) to the first day of the last menstrual period. This assumes a 28-day cycle with ovulation on day 14. It is the most commonly used method for estimating due dates.
Can my due date change?
Yes. Your due date may be adjusted during pregnancy based on ultrasound measurements, especially in the first trimester. If the ultrasound-based due date differs significantly from the LMP-based date, your healthcare provider may update it. Irregular cycles can also cause the initial estimate to be adjusted.
Related Tools
Date Calculator · Age Calculator · Event Countdown · Calorie Calculator · Water Intake Calculator