Assoc. Prof. Sabri Berkem Ökten Gestational Age Calculator Enter the first day of your last menstrual period: Day: Month: JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember Year: – According to these data, you are currently weeks days pregnant. ( there may be a margin of error of ±3 days). Estimated Date of Delivery (40 weeks): Contact Us