Pregnancy Calculator
Find your due date and pregnancy week
Free Pregnancy Calculator — Estimated Due Date
Due date, pregnancy week and trimesters from your last period
Enter the first day of your last menstrual period (LMP) and your average cycle length; this tool calculates your estimated due date using Naegele's rule (LMP + 280 days, adjusted for cycle length). You'll see how many weeks and days pregnant you are today, your current trimester, the estimated conception date, the start of the 2nd and 3rd trimesters and the days remaining. Your data stays on your device — nothing is sent to a server. Results are estimates: for definitive dating, always rely on your doctor's ultrasound measurements.
Features
Estimated Due Date
Naegele's rule with cycle-length adjustment
Pregnancy Week
How many weeks and days pregnant you are today
Trimester Dates
2nd and 3rd trimester starts plus days to go
100% Private
Your data never leaves your device
Pregnancy Timeline
Trimesters
- 1st trimester: weeks 1–13
- 2nd trimester: weeks 14–27
- 3rd trimester: weeks 28–40
- Term: week 40 (37–42 weeks is normal)
How it's calculated
- Due date = LMP + 280 days
- Cycle adjustment: + (cycle − 28) days
- Est. conception ≈ LMP + 14 days (cycle-adjusted)
- Pregnancy weeks count from the LMP
Frequently Asked Questions
How is the due date calculated?
With Naegele's rule: 280 days (40 weeks) are added to the first day of your last period, adjusted if your cycle differs from 28 days.
How do I know how many weeks pregnant I am?
Pregnancy weeks are counted from the last period date; the tool shows today's week and day automatically.
How accurate is the result?
Only about 4% of babies arrive exactly on their due date; most births happen between weeks 37 and 42. A first-trimester ultrasound is the most accurate dating method.
What if my cycles are irregular?
With irregular cycles the LMP method can be off; rely on your doctor's ultrasound dating instead. This tool is informational, not medical advice.
Is my data stored?
No. Your dates are saved only on your own device and are never sent to a server.