Naegle's Rule

• 1). Determine the first day of your last normal menstrual period using a calendar.
  
  
• 2). Count backward three months using a calendar.
  
  
• 3). Add seven days to the date using a calculator or a pen and paper.
  
  
• 4). Adjust the year if needed.
  
  

Last Menstrual Period Method

• 1). Determine the first day of your last normal menstrual period.
  
  
• 2). Add 14 days to determine the date of conception.
  
  
• 3). Add 266 days to this date.
  
  
• 4). Adjust the year if needed.
  
  

Conception Date

• 1). Determine the date of conception.
  
  
• 2). Add 266 days to this date.
  
  
• 3). Adjust the year if needed.
  
  

Online Due Date Calculator

• 1). Input the first day of your last normal menstrual period.
  
  
• 2). Input the average length of your menstrual cycle if required.
  
  
• 3). Press enter or follow the onscreen prompts to calculate the estimated pregnancy due date.