Gestational Age Calculator & Term Chart

A gestational age calculator is a simple tool used to determine how far along you are in your pregnancy. This is one of the vital calculators for expectant moms.

What is Gestation Age?

In obstetrics, the age of an embryo, fetus or newborn starting from the first day of the last menstrual period (LMP) is referred to as Gestational Age (GA). It is simply the age of a pregnancy. It is measured or calculated in weeks.

It also serves as a reference value to determine the stage of growth and physical development of a fetus. Gestational age is used to determine the progress, growth of pregnancy and fetus, and possible due date.

Gestational Age Calculator

To help you calculate your gestation age easily, we have created the online gestational age calculator below. This calculator is easy to use. You only need to input the starting date of your LMP and leave the calculator to do the rest.

This gestational age calculator will enable you to know your gestational age based on the start date of your LMP. Simply select the start date of your last menstrual period and click the Calculate button. Your gestational age will be calculated and shown instantly.


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Note: If you have irregular periods or your menstrual cycles usually exceed 28 days, this GA calculator may not be accurate. In these cases, an ultrasound or sonogram may be the only means to determine your gestational age more accurately.

How is the gestational age result interpreted?

After knowing how many weeks you are pregnant with the help of this calculator, use the chart below to know the stage of growth of the fetus. For example, if the calculator shows anything less than 37 weeks, the pregnancy is Preterm. If it shows 39 weeks 2 days, the pregnancy is Full Term.

Term Pregnancy Chart

Gestational AgeTerm
Less than 37 weeksPreterm
Between 37 weeks and 38 weeks 6 daysEarly Term
Between 39 weeks and 40 weeks 6 daysFull Term
Between 41 weeks and 41 weeks 6 daysLate Term
42 weeks and beyondPostterm
Term Pregnancy Chart