Due Date Calculator MY
Estimate your pregnancy due date from the last menstrual period (Naegele’s rule).
How it works
Enter a date of birth and an "as of" date to get exact age in years, months and days, plus the total in days and weeks.
Frequently asked questions
How is a due date calculated?
It typically adds 280 days (40 weeks) to the first day of your last menstrual period, known as Naegele’s rule.
What is Naegele’s rule?
A standard estimate: take the first day of the last period, subtract three months and add seven days, or equivalently add 280 days.
How accurate is an estimated due date?
It is an approximation. Few babies arrive exactly on it, and full term spans roughly 37 to 42 weeks.
What if my cycle is irregular?
The LMP method may be less accurate, since it assumes a regular 28-day cycle. A dating ultrasound gives a better estimate.
Can the due date change?
Yes. Providers may adjust it based on ultrasound measurements, especially an early scan, which is often more precise than the LMP date.
Is this a substitute for medical advice?
No. It is a general estimate for planning. Your healthcare provider gives the definitive assessment of your pregnancy.
How a due date is estimated
A pregnancy due date is an estimate of when a baby is likely to arrive, about 40 weeks from the start of the last menstrual period (LMP). This calculator uses the standard method to project that date, though only a minority of babies arrive exactly on it.
Naegele’s rule
The common formula, Naegele’s rule, adds 280 days (40 weeks) to the first day of the LMP. An equivalent shortcut takes the LMP, subtracts three months and adds seven days. For an LMP of January 1, that points to an estimated due date around October 8.
Why it is only an estimate
The method assumes a regular 28-day cycle with ovulation around day 14, so it can be off if cycles are longer, shorter or irregular. A full-term pregnancy is generally considered anywhere from about 37 to 42 weeks, so a range matters more than a single day.
This tool gives a general estimate for planning and is not a substitute for medical care. An ultrasound dating scan and your healthcare provider give the most accurate assessment of your pregnancy timeline.
Results are estimates for general guidance in Malaysia and may not reflect the latest local rates, fees or rules. Check official sources before making decisions.