Pregnancy Calculator
Calculate pregnancy week, trimester, and key milestone dates.
Pregnancy Calculator
Calculate pregnancy week, trimester, and key milestone dates.
Pregnancy Due Date — Naegele's Rule
ℹ️ Only 5% of babies are born on their exact due date. Dates are estimates only.
Disclaimer
Results provided by this calculator are for informational and educational purposes only. They are based on the values you enter and standard formulas, and should not be considered financial, medical, legal, or professional advice. Always consult a qualified professional before making important decisions based on these results. Roughtools makes no warranties regarding the accuracy or completeness of these calculations for your specific situation.
Frequently Asked Questions
Pro Tips
Only about 5% of babies are born on their due date — the Naegele's Rule date is the midpoint of a 5-week window. Don't over-plan for the exact date.
Early ultrasound (6-10 weeks) is more accurate for dating than last menstrual period if your cycles are irregular. Your OB may adjust your due date based on ultrasound.
Gestational age in weeks is counted from LMP, not conception. "6 weeks pregnant" means 6 weeks since your last period, which is only 4 weeks since likely conception.
Track your symptoms week by week using the trimester milestones. Many pregnancy apps let you export a report — useful to share with your healthcare provider.
When to Use This Calculator
Calculate your due date to plan maternity leave timing, financial preparation, and childcare arrangements.
Calculate your estimated due date in advance so you can ask the right questions at your first OB appointment.
Know your due date to schedule the baby shower at the right time — typically 4–6 weeks before delivery.
Share your due date with family and friends as a planning tool, while reminding them only 5% of babies arrive on that date.
Parents of multiple children often plan birth timing around school enrollment cutoffs — use the due date to estimate.
About the Pregnancy Calculator
The Pregnancy Calculator determines your current gestational age in weeks and days, identifies your trimester, and maps out key milestones including heartbeat detection (week 6), nuchal screening (weeks 11–13), anatomy scan (week 20), viability (week 24), and full-term (week 37). Enter your last menstrual period or known due date.
How to Use the Pregnancy Calculator
- 1
Select your input type: last menstrual period (LMP) or due date.
- 2
Enter the date.
- 3
Click Calculate to see gestational age, trimester, and milestone dates.
- 4
Scroll through the week-by-week timeline for development highlights.
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