Pregnancy Conception Date Calculator
Estimate conception date, due date, and key pregnancy milestones accurately
Pregnancy Timeline Calculator
Calculate backwards from last menstrual period (LMP) or forward from known conception. Shows 40-week gestation timeline with trimesters, fetal development stages, and important dates. Naegele’s rule + ultrasound adjustments for precision.
Multiple Calculation Methods
- Enter Last Menstrual Period (LMP) date OR known conception date.
- Select cycle length (28 days standard).
- Get complete pregnancy timeline with all milestones.
FAQs
- LMP vs ultrasound accuracy?
- LMP ±5-7 days. 1st trimester ultrasound ±3-5 days. 2nd trimester ±7-10 days.
- Irregular cycles affect calculation?
- Yes – adjust cycle length. Ovulation kits or BBT tracking more precise (±1-2 days).
- Why 266 days from conception?
- Human gestation = 38 weeks (266 days) from conception, 40 weeks (280 days) from LMP.
- Can I calculate from positive test?
- Yes – add 2 weeks to positive hCG test date for due date (test ~14 days post-conception).
- IVF pregnancy calculation?
- Use embryo transfer date + 2 weeks (blastocyst) or + 5 days (day 5 embryo).