If you need bmi (body mass index), minimum weight gain and maximum weight gain and you already have height, weight, twins, week and one way, this calculator does the substitution for you. It suits a quick check, a homework answer you want to confirm, or any figure you need to sanity test.
What Is the Pregnancy Weight Gain Calculator?
The pregnancy weight gain calculator gives you an estimate of bmi (body mass index), minimum weight gain and maximum weight gain based on height, weight, twins, week and one way.
It is a quick reference figure rather than a diagnosis, and it is most useful for tracking how a number moves over time rather than for interpreting a single reading.
How the Pregnancy Weight Gain Estimate Is Worked Out
The calculation follows published reference relationships, so it is a reasonable approximation when the inputs are accurate. It assumes an average adult and does not account for individual variation.
If you are comparing two people, or the same person over a period of weeks, keep the method and the inputs identical. A change in the method can easily look like a change in the person.
What This Calculator Does Not Do
It does not diagnose anything, and it does not replace advice from a clinician. If a figure comes out at an extreme, or if it differs sharply from what you expect, that is a reason to speak to a professional rather than to adjust the inputs.
Nothing you type here is stored or sent anywhere. The whole calculation happens in your browser.
A Worked Example
Working through an example, with height set to 10, weight set to 5, twins set to 1, the calculator returns bmi (body mass index) of 0.05, and you are... of 1, and minimum weight gain of 0.04. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out bmi (body mass index)?
Enter height, weight, twins, week and one way. The calculator then works through the relationship and reports bmi (body mass index), minimum weight gain and maximum weight gain.
What does the pregnancy weight gain actually calculate?
It takes height, weight, twins, week and one way and converts them into bmi (body mass index), minimum weight gain and maximum weight gain using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter height?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Why does a small change in one value move the answer so much?
That happens when an output depends on a ratio, because dividing by a small number magnifies any change in it. Check the units first, then check whether the value you entered is in the range the relationship was designed for.
Do I have to fill in every field?
Only the fields a particular result depends on. If you leave one blank, the results that need it simply show a note instead of a number, and everything else still works.