Calculator tool
This calculator uses standard obstetric dating assumptions: 280 days from the first day of the last menstrual period, about 266 days from conception, ultrasound dating from the gestational age measured on the scan date, and IVF dating from transfer date minus embryo age.
Review the inputs carefully and treat the output as an estimate. For decisions involving money, taxes, health, law, or security, compare the result with trusted professional guidance when needed.
Which dating method should I use?
Use the earliest reliable clinical dating available. First-trimester ultrasound and IVF transfer dates are usually more precise than a remembered last period date.
Is the pregnancy week exact?
No. Pregnancy week and due date are estimates. Confirm medical timing, test windows, and delivery planning with a qualified healthcare professional.
Due Date Calculator
Calculate an estimated due date from LMP, conception date, ultrasound gestational age, or IVF embryo transfer.
Open toolConception Calculator
Estimate when conception likely occurred from an estimated due date, last menstrual period, or ultrasound dating.
Open toolPregnancy Weight Gain Calculator
Calculate recommended total and weekly pregnancy weight gain based on pre-pregnancy BMI and whether you are carrying one baby or twins.
Open tool