What is the Pregnancy Week Calculator?
The Pregnancy Week Calculator converts an established estimated due date into gestational week and day on a selected date. This is helpful when your prenatal EDD is already known and you want to map appointments or calendar dates to pregnancy timing.
How does the Pregnancy Week Calculator work?
A standard pregnancy due date corresponds to 40 weeks, or 280 gestational days. The calculator counts how many days remain until the EDD and subtracts that number from 280, then converts the resulting gestational days into weeks and days.
What formula or rule does it use?
Gestational days = 280 − days remaining until the estimated due date. The dynamic “How this answer was calculated” panel substitutes your entered values into that rule after a valid calculation.
How should you use this calculator?
Enter the EDD you are using in prenatal care and choose the calendar date you want to check. For an LMP-based estimate of the EDD itself, use the Due Date Calculator.
How should you understand the result?
“Week 33 + 3 days,” for example, means 33 complete gestational weeks plus 3 days. The result also displays the estimated LMP date implied by the EDD and the number of days remaining until that due date.
What are the limitations?
This calculator is only as appropriate as the EDD entered. If a clinician has revised the pregnancy due date after ultrasound or ART dating, use that established EDD rather than an older calendar estimate.
Who can use this calculator?
It is useful for pregnancy calendar planning after an EDD has been established. To see trimester boundaries, compare the result with the Pregnancy Trimester Calculator; for IVF timing, see the IVF Due Date Calculator. For an LMP-based all-in-one timeline, use the Pregnancy Calculator.
Frequently asked questions about Pregnancy Week
Sources and methodology
Methodology and interpretation are grounded in the following professional or government references.