Pregnancy Calculator: How Far Along Is Your Pregnancy?

Author: Claire

pregnancy calculator gestational length

By: Claire

What Is Gestational Length?

You’ve confirmed that you’re pregnant. You’ve decided that you want to terminate the pregnancy. So what next?

Depending on where you live, there are a number of local and/or international providers that may be able to help support you with a safe abortion option. Many of these organizations will start by asking you some basic information about the pregnancy in order to determine your safe next steps. One of these questions will most likely be, “What is the gestational length of the pregnancy?”

But what does “gestational length” mean? When providers ask for the gestational length, they’re asking how far along the pregnancy is, or how long you’ve been pregnant. This calculation is not always as straightforward as it seems.

The Pregnancy Calculator: Calculating Gestational Length

Many women assume that they should start counting how long they’ve been pregnant since the moment they confirmed they were pregnant. For example, if a woman had a positive pregnancy test on Wednesday, August 1st and was asked for the gestational length at a medical appointment on August 14th, she might say that she was 2 weeks pregnant. This is actually incorrect.

The correct way to calculate the gestational length of a pregnancy requires a woman to think back to the last time she got her menstrual period. Gestational length is measured from the first day of her last period.

Let’s revisit our original example with the woman who had a positive pregnancy test on August 1st. In order to help her calculate the gestational length, her care provider could ask her, “When did you get your last menstrual period?” The woman may think back and remember, “My last period started on Sunday July 1st and I bled until Thursday July 5th.”

The care provider could take out her calendar and circle Sunday July 1st. This is when we begin counting the number of weeks for the gestational age. The care provider would then move her finger down the calendar one week to Sunday July 8th. This counts as the first week of pregnancy. Next, the care provider would move her finger to Sunday July 15th. This represents the 2nd week of pregnancy. The care provider would continue counting the weeks this way with the woman.

Based on this method, they would determine that when the woman had her positive pregnancy test on August 1st, the pregnancy was 4 weeks and 3 days along. By the time of her appointment on August 14th, the pregnancy would be 6 weeks and 2 days.

And why is the gestational length so important? Depending on how far along the pregnancy is, women and care providers may decide on different methods of safe abortion.

Medical abortion, or abortion with pills, is commonly recommended for women with early pregnancies. However, as the gestational length advances, providers may choose to slightly alter the dosage and administration of the abortion pills. This is to protect the health and safety of the woman.

If you have questions about calculating the gestational length of a pregnancy, or if you are looking for information and resources about safe medical abortion, feel free to connect with us. You can visit our website or follow us on social media: FacebookTwitterInstagram, or Pinterest.

Claire is a teacher, reproductive rights advocate, and the manager of is Affiliated With A Registered U.S.-Based 501c(3) Non-Profit Organization. provides Content Intended For Informational Purposes Only And Is Not Affiliated With A Medical Organization.

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