What is the Pregnancy Calculator?
The Pregnancy Calculator combines gestational age, estimated due date, estimated conception timing, trimester, days remaining, and 40-week progress in one result. If you only need the expected delivery date, the Due Date Calculator is the simpler option.
How does the Pregnancy Calculator work?
The calculator counts calendar days from the LMP to the selected date, divides that interval into completed weeks plus remaining days, and separately calculates an EDD from LMP and cycle length. This keeps pregnancy progress and the estimated delivery date transparent.
What formula or rule does it use?
Gestational age = selected date − LMP; EDD uses 280 days adjusted for cycle length. 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 first day of the LMP, choose the date on which you want to measure pregnancy progress, and use your average cycle length. If a clinician has already established an EDD, you can cross-check calendar timing with the Pregnancy Week Calculator.
How should you understand the result?
A result such as 16 weeks 2 days means 16 complete gestational weeks plus 2 additional days have elapsed from the LMP convention. The trimester label and progress percentage are calendar summaries, while the EDD remains an estimate.
What are the limitations?
Pregnancy dating is not the same as exact fetal age. Obstetric gestational age convention starts from LMP, approximately two weeks before conception in a typical 28-day cycle. Ultrasound or ART-derived dating may be more appropriate in specific pregnancies.
Who can use this calculator?
Use this tool for a combined pregnancy-timeline overview. For conception timing specifically, use the Conception Date Calculator; for trimester boundaries, use the Pregnancy Trimester Calculator.
Frequently asked questions about Pregnancy
Sources and methodology
Methodology and interpretation are grounded in the following professional or government references.