Pregnancy Due Date Calculator
Estimate your baby's due date, current gestational age, trimester, and key pregnancy milestones.
How to Use
- Select your calculation method: "Last Menstrual Period (LMP)" if you know the first day of your last period, or "Conception Date" if you know your approximate conception date.
- Enter the relevant date using the date picker. For LMP mode, optionally adjust your average cycle length if it differs from the standard 28 days.
- Click "Calculate Due Date" to see your estimated due date, current gestational age, trimester, and days remaining.
- Review the key milestone dates to track important stages of your pregnancy journey.
Frequently Asked Questions
How is the due date calculated from LMP?
The due date is calculated using Naegele's rule with a cycle length adjustment. From your LMP date, the calculator adds 280 days (40 weeks) and then adjusts for your cycle length. If your cycle is longer than 28 days, the due date shifts later by the difference; if shorter, it shifts earlier. This accounts for ovulation timing differences between cycle lengths.
How is the due date calculated from conception date?
When using the conception date, the calculator adds 266 days (38 weeks) to the provided date. This is because pregnancy is approximately 38 weeks from conception, or 40 weeks from the last menstrual period (since conception typically occurs about 2 weeks after the start of the menstrual cycle).
What does gestational age mean?
Gestational age is the number of weeks and days since the first day of your last menstrual period (LMP). It is the standard way pregnancy duration is measured by healthcare providers. A full-term pregnancy is typically 39 to 40 weeks gestational age.
How accurate is this due date estimate?
Due date estimates are approximate. Only about 5% of babies are born on the exact estimated due date. Most babies arrive within a two-week window around the due date. Factors such as irregular cycles, inaccurate date recall, and individual variation affect accuracy. An ultrasound in the first trimester provides the most accurate dating.