☾ Pregnancy Due Date Calculator
Estimate your due date, current pregnancy week, and trimester using Naegele's rule.
Sync to Your Cycle
Get personalized daily workouts, cycle tracking, and custom nutrition plans matching your current phase inside the Moona Web App.
Start Free AI Coaching ✦🧬 Understanding Pregnancy Dating
Pregnancy is dated from the first day of your last menstrual period (LMP), not from conception. This means you are considered 'pregnant' for about 2 weeks before conception actually occurs.
✦ How is the due date calculated? ↓
We use Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period. If your cycle is not 28 days, the calculation adjusts by adding or subtracting the difference. For example, a 30-day cycle adds 2 extra days to the due date.
✦ How accurate is the due date estimate? ↓
Naegele's rule is most accurate for women with regular 28-day cycles. Only about 5% of babies arrive on the exact due date. Most are born within a window of 37–42 weeks. First-trimester ultrasound dating is generally considered more accurate (±5 days) compared to LMP-based calculations (±2 weeks).
✦ Can I exercise during pregnancy? ↓
Yes! The American College of Obstetricians and Gynecologists recommends at least 150 minutes of moderate-intensity exercise per week during pregnancy. Activities like walking, swimming, prenatal yoga, and modified strength training are excellent options. Always consult your doctor before starting or continuing an exercise program during pregnancy.
✦ What if I don't know my LMP date? ↓
If your LMP date is uncertain — due to irregular cycles, breakthrough bleeding, or recent contraceptive use — a dating ultrasound in the first trimester is the gold standard. The ultrasound measures crown-rump length (CRL) of the embryo, which correlates very closely with gestational age in weeks 6–13.
✦ Is it safe to exercise throughout all trimesters? ↓
The American College of Obstetricians and Gynecologists (ACOG) recommends 150 minutes of moderate-intensity aerobic activity per week throughout pregnancy for healthy women. Walking, swimming, stationary cycling, and modified strength training are all safe. Avoid contact sports, supine exercises after the first trimester, and activities with fall risk. Always clear your specific routine with your provider.
✦ How does a longer or shorter cycle change the due date? ↓
Naegele's rule assumes ovulation on day 14 of a 28-day cycle. If your cycle is 35 days, ovulation likely occurs around day 21 — a 7-day delay — pushing your due date out by one week. Conversely, a 24-day cycle may shift ovulation to day 10, moving the due date 4 days earlier. The calculator handles this adjustment automatically.
📖 How to Calculate Your Due Date
Enter the first day of your last menstrual period (LMP) and your average cycle length. The calculator applies Naegele's rule — adding 280 days to your LMP — then adjusts for cycle lengths that differ from the standard 28 days.
If your cycle is longer than 28 days, your due date shifts later; shorter cycles move it earlier. For example, a 32-day cycle adds 4 extra days to the standard calculation, placing your due date at 284 days from LMP.
📊 Understanding Your Pregnancy Timeline
Your estimated due date (EDD) marks the completion of 40 gestational weeks. The current week counter tells you which week you're in right now, while the trimester indicator groups your pregnancy into the three major developmental stages.
Keep in mind that only about 5% of births occur on the exact due date. Full-term delivery spans weeks 37–42, so your EDD is a midpoint estimate rather than a fixed deadline. First-trimester ultrasound dating (available from week 8) typically narrows accuracy to ±5 days.
⚕️ When to Contact Your Healthcare Provider
Contact your OB-GYN or midwife as soon as you receive a positive pregnancy test to schedule your first prenatal visit (typically weeks 8–10). Seek immediate care if you experience heavy vaginal bleeding, severe abdominal pain, persistent vomiting preventing hydration, or a fever above 38°C (100.4°F) at any point during pregnancy.