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What is a Pregnancy Calculator?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

A pregnancy calculator can actually refer to a number of different online calculators or formulas you can try at home to check things about a pregnancy like due date, to determine when you got pregnant, or if you might be pregnant. You’ll also see free pregnancy weight calculators that give you an estimate of appropriate weight gain during a pregnancy. Similarly, you can use an online pregnancy calculator to determine when the best time of the month would be to get pregnant based on review of your average cycle length.

This last calculator can be used with things like ovulation tests to determine when you are most likely to be ovulating. This can be helpful information both if you’re trying to get pregnant and if you’re trying to avoid getting pregnant. Generally, ovulation begins about 12-14 days after the beginning of your last period, and if you have regular cycles you may be able to predict ovulation based on this. If your periods are irregular, it is much harder to predict, and ovulation can vary in even the most regular cycles. You should probably not use a pregnancy calculator as a sole means of birth control if you are trying to avoid pregnancy.

Pregnancy calculators can help a woman figure out the due date of her baby.
Pregnancy calculators can help a woman figure out the due date of her baby.

Sometimes a pregnancy calculator that is used to determine due date is based pretty much on when you ovulated. When due date is calculated, weeks pregnant may be determined as two weeks after your last period began. Alternately, length of pregnancy could be calculated based on first day of your last period with everything beginning on that day counting as “pregnant” in a total weeks count.

Consulting with a doctor is the most accurate way to calculate pregnancy.
Consulting with a doctor is the most accurate way to calculate pregnancy.

If you think you might be pregnant, you can find free pregnancy calculators online that may help you decide whether you may have missed a period. Of course, this depends on knowing when your last cycle began, and knowing when you might have conceived. Some pregnancy calendar types like this may also evaluate potential symptoms of pregnancy as part of a “guess.”

An online pregnancy calculator can determine when the best time of the month would be to get pregnant based on a review of an average menstrual cycle length.
An online pregnancy calculator can determine when the best time of the month would be to get pregnant based on a review of an average menstrual cycle length.

Online pregnancy calendars for weight gain also work on some guesswork, and should not be considered good medical guides or substitutes for regular medical care. These often work based on height, pre-pregnancy weight, and the number of months you are pregnant. They are roughly as helpful as guidelines for weight gain in most books on becoming a mom.

Some expectant mothers calculate and track their progress using online tools.
Some expectant mothers calculate and track their progress using online tools.

With most free online pregnancy calculator types, you are being given very general information that is not specific enough to your condition. They may be fun to use for informational purposes, but they are not as accurate as true medical calculation of your due date, weight gain or potential pregnancy. While you may consider these a good first step, each woman is different. If you think you are pregnant, rely on pregnancy tests (either home or doctor initiated) rather than online information to guide your next steps. When you know you are pregnant, use doctor's advice and not dubious or general online information to help you have a healthy pregnancy.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...

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    • Pregnancy calculators can help a woman figure out the due date of her baby.
      By: lanamaster
      Pregnancy calculators can help a woman figure out the due date of her baby.
    • Consulting with a doctor is the most accurate way to calculate pregnancy.
      By: pressmaster
      Consulting with a doctor is the most accurate way to calculate pregnancy.
    • An online pregnancy calculator can determine when the best time of the month would be to get pregnant based on a review of an average menstrual cycle length.
      By: CandyBox Images
      An online pregnancy calculator can determine when the best time of the month would be to get pregnant based on a review of an average menstrual cycle length.
    • Some expectant mothers calculate and track their progress using online tools.
      By: Felix Mizioznikov
      Some expectant mothers calculate and track their progress using online tools.