Pregnancy Due Date Calculator
Estimate your pregnancy due date from your last menstrual period, conception date, or IVF embryo transfer date.
How this calculator works
How to use this calculator
Choose the calculation method, enter the relevant date, and click Calculate Due Date. For the LMP method, use the first day of your last menstrual period. For conception, use the estimated conception date. For IVF, choose the correct embryo age and enter the transfer date.
Formula used
Last menstrual period method: Estimated due date = first day of LMP + 280 days.
Conception method: Estimated due date = conception date + 266 days.
IVF 3-day embryo method: Estimated due date = transfer date + 263 days.
IVF 5-day embryo method: Estimated due date = transfer date + 261 days.
Example calculation
If the first day of the last menstrual period was January 1, 2026, the estimated due date is October 8, 2026.
What the result means
The result is an estimated due date, not a guaranteed delivery date. Due dates are used as a planning guide and may be adjusted by a healthcare professional using ultrasound or clinical information.
Frequently asked questions
Is the due date exact?
No. It is an estimate. Many babies arrive before or after the estimated due date.
Which method should I use?
Use LMP if you know the first day of your last period and have regular cycles. Use conception or IVF methods only if those dates are known.
Why does pregnancy count from the last period?
Clinical pregnancy dating commonly counts from the first day of the last menstrual period, which is about two weeks before conception in a typical 28-day cycle.
Should I use this instead of my doctor’s due date?
No. Use your healthcare provider’s estimated due date for medical care.