Health
Pregnancy Due Date Calculator
Estimate your baby's due date from the first day of your last period, plus your current week and trimester.
Estimated due date
Wednesday, May 5, 2027
Current stage
10 weeks 0 days
Trimester
1
Days to go
210
An estimate based on Naegele's rule. Your doctor or midwife will confirm the date.
Pregnancy Due Date Calculator
Estimate your baby's due date from the first day of your last period, plus your current week and trimester.
The Pregnancy Due Date Calculator provides an estimate of your baby's expected arrival using Naegele's rule. This tool helps expectant parents understand their current stage of pregnancy and prepare for upcoming milestones.
To use the calculator, input the first day of your last menstrual period (LMP) and your typical cycle length in days (the default is 28). The tool will then calculate the estimated due date, your current gestational age in weeks and days, your trimester, and how many days remain.
For example, if your last period started 70 days ago with a 28-day cycle, the tool estimates your current stage as 10 weeks and 0 days, placing you in the first trimester. This allows you to track progress accurately.
Please note that this is an estimate and not medical advice. Only a healthcare professional can confirm your exact due date through clinical assessments. The tool runs locally in your browser to maintain your privacy.
Key Features
- Pregnancy Due Date Calculator: 100% free, no sign-up
- Instant results as you type
- Private: runs in your browser
- Works on phone, tablet and desktop
- Available in English, Spanish, French and Arabic
How it works
The calculator estimates the due date by adding 280 days (40 weeks) to the first day of the last period, adjusted for the individual's average cycle length.
Worked example
Frequently asked questions
Is this 100% accurate?
No, very few babies are born on their exact due date. It is just an estimation.
What if my cycles are irregular?
Naegele's rule assumes a standard 28-day cycle; irregular cycles may make the estimate less precise.
Does this account for leap years?
The underlying date logic handles standard calendar variations.
Should I use this to replace doctor visits?
No, this is for informational purposes only. Always follow your medical provider's guidance.
How do I know my trimester?
The calculator divides your gestational weeks into three blocks: 1–13 (1st), 14–27 (2nd), and 28+ (3rd).