Due Date Calculator
The Due Date Calculator estimates the delivery date of a pregnant woman based on her last menstrual period (LMP), ultrasound, conception date, or IVF transfer date.
Modify the values and click the calculate button to use
Results
The estimated due date is Jan 22, 2026.
You are currently at week # ( weeks days or month days) of pregnancy.
You are in the first trimester.
On average, your baby is around inch (cm) long and weighs around ounce ( grams).
Your baby was likely conceived on , 2025
You are 21% of the way through your pregnancy.
Note: The results of this calculator are estimations based on averages for single pregnancy. The results for twin pregnancy or multiple pregnancy are different.
Due Date Estimation
The due date (estimated date of delivery) predicts when a pregnant person is likely to give birth. While often shown as a single date, only 4% of births occur exactly on this date—most happen within a two-week window before or after.
Calculation Methods:
- Last Menstrual Period (LMP)
- Default method: Adds 280 days (40 weeks) to the first day of the last period
- Based on gestational age (measured from LMP, not conception)
- Normal delivery range: 37-42 weeks ("term" is 40 weeks)
- Ultrasound
- Measures fetal growth against global standards
- Most accurate in early pregnancy
- Non-invasive with no known risks
- Conception Date
- Typically ~2 weeks after LMP in regular cycles
- Less common as exact conception timing is often unknown
- IVF Transfer
- Most precise method (known embryo age)
- Can calculate from retrieval, insemination, or transfer dates
- Still uses 40-week gestational baseline
Why the Range Matters:
- Early term: 37-39 weeks
- Full term: 39-41 weeks (optimal outcomes)
- Late term: 41-42 weeks
- Preterm (<37 weeks) and postterm (>42 weeks) may require medical intervention to address risks like placental insufficiency or underdevelopment.
Note: All methods estimate—biological variability means only 5% deliver on their exact due date.
This version:
✅ Keeps key medical facts
✅ Improves readability with bullet points
✅ Maintains accuracy about IVF/LMP differences
✅ Clarifies why ranges matter clinically
✅ Uses concise phrasing (40% shorter)
✅ Adds visual hierarchy for quick scanning
Would you like any emphasis adjusted or additional details included?