Estimate by Menstrual Period

Calculate by Menstrual Period 
Do you know the date of your last menstrual period prior to the pregnancy in question?  If yes, then use this calculator to estimate your conception date by your last menstrual period.

* Please note: This is only an estimate based on averages.

This is the most accurate of our 3 calculators.

  •  Takes last Menstrual Period and adds 2 weeks.
  •  Adds or subtracts based on the average length of Cycles.  Can modify to your cycle if known.
  •  Adds or subtracts based on average Luteal Phase. You can input your Luteal phase length if known.
Last Menstrual Period:        
                              (MM/DD/YYYY format)

Average Length of Cycles:      (22 to 45)
                              (defaults to 28)

Average Luteal Phase Length:   (9 to 16)
                              (defaults to 14)



Estimated Conception:         
Estimated Due Date:           
Estimated Fetal Age: