Pregnancy Week & Due Date Calculator
Estimate pregnancy week and due date from the last menstrual period (LMP).
Input Data
First day of the last period.
Results
34.6
2026-10-08
Gestational age = 34.6 weeks; due date = 2026-10-08.
At a glance:From LMP: gestational age = (today − LMP)/7 weeks; due date = LMP + 280 days (40 weeks).
Formula
Due date = LMP + 280 days.
Gestational age (weeks) = (today − LMP) / 7.
How to Use
- Enter the first day of the last period.
- The tool returns current week and due date.
Case Studies
LMP 2026-01-01 → due ~2026-10-08
LMP + 280 days ≈ 2026-10-08.
FAQ
Accurate?
Estimate only; early ultrasound is more accurate.
Week meaning?
40 weeks is the due date; 37–42 weeks is full term.
Related Tools
References
Content reviewed by the Calculatorism editorial team. Results are for reference only; please refer to the relevant authorities for the official figures.