Pregnancy Calculator

Gestational age counts from the last period, not conception. Enter LMP to locate today on the timeline.

First day of last period

Enter the required values above to see your result.

How the Pregnancy Calculator works

The calculation follows the standard method used across the US — no shortcuts, no hidden assumptions. Here is exactly what happens behind the scenes:

How does the Pregnancy Calculator work?

Enter your numbers above and results update instantly using standard formulas, computed entirely on your device.

Is the Pregnancy Calculator free to use?

Yes — completely free with no signup required, and it works on phones, tablets, and desktops.

Predict your due date from the first day of your last period (adjusted for cycle length) or from conception.

Fitness & Health

Recommended pregnancy weight gain ranges by pre-pregnancy BMI and current week (IOM/NAM guidelines).

Fitness & Health

Predict ovulation dates and fertile windows from cycle start and length over coming months.

Fitness & Health