Why count from LMP instead of conception?
LMP provides consistent reference point since conception date is often unknown. Adds ~2 weeks to fetal age.
Health Fitness
Pregnancy Week Calculator
Estimate pregnancy week with quick inputs.
Fast, practical estimates
Adjust inputs for the most useful result.
What this calculator does
A pregnancy week calculator converts days since LMP into weeks and days format (e.g., '24 weeks, 3 days'). Medical appointments and developmental milestones are tracked by gestational week.
How it works
Enter LMP and current date. Calculator divides elapsed days by 7 for weeks, with remainder as days.
Formula
Weeks = (Current Date - LMP) ÷ 7. Days = Remainder. Example: 171 days = 24 weeks, 3 days.
Tips for using this calculator
- Gestational age starts from LMP, not conception
- Fetal development milestones are week-specific
- Medical records use weeks+days format
- Full term begins at 37 weeks
- Due date is at 40 weeks
Frequently asked questions
What's the difference between weeks and months?
40 weeks ≈ 9 months + 1 week. Months are less precise; medical care uses weeks.
When am I considered full term?
37-42 weeks is full term. Before 37 weeks is preterm; after 42 is post-term.