Calculate Gestational Age

*Please note that the calculation results may differ from actual values.

Formula for Calculating Gestational Age

This calculator uses the first day of your last menstrual period as the start of your pregnancy (0 weeks, 0 days) and calculates your estimated due date as 40 weeks (280 days) from that date.

• Calculated from the first day of your last menstrual period: Gestational age = “Date you want to check” – First day of your last menstrual period


• Calculated from the estimated due date: Gestational age = “Date you want to check” – (Estimated due date – 40 weeks)

*This site assumes no responsibility whatsoever for calculation results or other information. We do not provide individual consultations.