Pregnancy & Ovulation Calculator
These utilities are provided by Util Monster (util.monster) -
util.monster
Purpose of This Calculator
This pregnancy calculator uses Naegele's Rule to accurately calculate your due date, ovulation date, and fertile window based on your last menstrual period. A free tool to help with pregnancy planning and preparation.
Pregnancy Information
Last Menstrual Period
Ovulation Date
Fertile Window
Current Pregnancy Week
Current Pregnancy Month
Days Until Due Date
Pregnancy Trimesters
1st Trimester (Early)
2nd Trimester (Mid)
3rd Trimester (Late)
How Due Date is Calculated
Naegele's Rule:
β’ Last menstrual period + 280 days (40 weeks)
β’ Or: First day of LMP - 3 months + 7 days
Ovulation Calculation:
β’ LMP + Cycle length - 14 days
β’ 28-day cycle: 14 days after period
Fertile Window:
β’ 5 days around ovulation (Ovulation -5 to +1)
β’ Sperm survival: 3-5 days
β’ Egg survival: 12-24 hours
Important Notes:
β’ This calculator provides estimates
β’ Accurate due date requires medical examination
β’ Actual delivery within Β±2 weeks of due date is normal