Type the date of your last period or the conception date and see the gestational age in weeks, the estimated due date and weekly milestones.
Gestational age is counted from the first day of the last menstrual period, not from conception. The convention dates from before ultrasound existed and it persists because it is the date most women know with certainty. The estimated due date — the DPP in Portuguese — is 280 days (40 weeks) from the LMP, a rule attributed to Franz Naegele in the 19th century. If you know the conception date instead, the calculator adds 14 days to align with the LMP convention, because ovulation typically happens around day 14 of the cycle.
The milestones shown are standard markers from obstetric references: when the heartbeat is detectable, when the morphological ultrasound is done, when viability begins. They are population averages, not predictions for a specific pregnancy — the ultrasound and the obstetrician are the sources that matter. The DPP itself is an estimate: only about 4% of babies arrive on the exact date, and the normal window runs from 37 to 42 weeks.
Everything runs in your browser and nothing is stored or logged. This is an informational tool, not a medical device. It does not replace prenatal care, an ultrasound, or a conversation with the obstetrician.
From LMP: gestational age = today − LMP in days; EDD = LMP + 280 days. From conception: LMP is estimated as conception − 14 days. Weeks = floor(days ÷ 7), remaining days = days mod 7.
Use the LMP if you know it — it is the standard convention and the one your obstetrician will use. Use the conception date only if you know it with confidence (for example, from IVF or from ovulation tracking).
Because the convention counts from the LMP, which is about two weeks before ovulation. At "2 weeks pregnant" by this convention, conception has not happened yet. The system is confusing but universal.
It is an estimate. About 4% of babies arrive on the EDD. The normal range is 37 to 42 weeks, and a first-trimester ultrasound adjusts the date more accurately than the Naegele rule.
No. It is a calculator that applies a standard formula. Prenatal care involves blood tests, ultrasounds, blood pressure monitoring and clinical judgment that no calculator can replace.
No. The dates you type are processed in JavaScript on your device and are not uploaded, stored or logged.
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