Pregnancy & Baby
Due date, conception date, weeks pregnant, baby growth, ovulation window — accurate tools backed by ACOG and WHO clinical guidelines for expecting families.
Pregnancy planning and tracking calculators — due date prediction (Naegele's rule), conception date estimation, weeks pregnant, ovulation day. Each uses the standard obstetric formulas as published by ACOG and used by Indian gynaecologists.
Pregnancy
What's here
Due date — based on last menstrual period (LMP) using Naegele's rule (LMP + 280 days, or LMP + 9 months + 7 days). Conception date back-calculated from LMP. Weeks pregnant from any reference date. Ovulation day for cycle planning.
These are general estimates — actual delivery typically occurs ±2 weeks around the predicted date. For high-precision tracking and any concerns, ultrasound dating (especially first-trimester) is more accurate than LMP-based calculations.
Frequently asked questions
How accurate is due date from LMP?
Naegele's rule (LMP + 280 days) assumes a 28-day cycle and ovulation on day 14. For women with regular 28-day cycles it's accurate within ±5-7 days. For irregular cycles or longer/shorter cycles, ultrasound dating in the first trimester is more accurate (within ±5 days even at 7-12 weeks).
When does pregnancy start counting?
Obstetric convention starts pregnancy week count from the first day of LMP, not from conception. So you're 'pregnant' for ~2 weeks before conception actually happens. Total length is 40 weeks LMP-to-due-date, but actual gestation from conception is ~38 weeks.
Should I use these calculators instead of seeing a doctor?
No — calculators are reference tools. For pregnancy management, regular antenatal visits with a gynaecologist are essential. Calculators help you plan and understand timelines but cannot replace clinical assessment, especially for high-risk pregnancies.
What's the most fertile window?
The 5 days before ovulation through ovulation day itself — typically days 9-14 of a 28-day cycle. Sperm survives up to 5 days in the reproductive tract; the egg survives 12-24 hours after ovulation. The ovulation calculator estimates the window based on cycle length.
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