BMI calculator

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6 Votes • 16 Comments
I find myself looking up my BMI about every other month, and I always have to go through searching for a calculator first.

A search in the format "BMI <number> <kg|lbs|stone> <number> <feet and inches|cm>" could result in the calculated BMI + maybe a link to the explanation of the value (Wikipedia) and/or a colored indicator showing if that BMI is "good" or "bad" (although this is a bit hard because BMI evaluation depends on age and sex).

I'd do this if you think this is an appropriate idea. (Easy to filter and easy to calculate).
• posted 3 years and 8 months ago In Development

javathunderman
What would be the sources required, or can this be done without API calls? Nonetheless, I'm all for it.
posted by javathunderman Community Leader3 years and 8 months ago Link
rixx
Can easily be done without API calls, just needs conversion of units and the BMI formula.
posted by rixx 3 years and 8 months ago Link
glennmatthew
This is a fixed forumula, where BMI = weight (kg) / heigh squared (m2). You'd need to use a calculator to convert imperial measurements to metric, which could be built into the tool.

Source: Hill, A, Marchese, R, 2011. The essential guide to fitness: for the fitness instructor. 2nd ed. page 103: Pearson Australia.

The actual problem here is grading people into a health risk, as the categories change from country to country. I would hate to see DDG just spitting out US-centric results, so you'd need 3 inputs:

1. Height
2. Weight
3. Nationality

My opinion- BMI is inherently flawed and should only be relied upon by general populations as a guide. Other measurements, such as waist to hip ratio (Van Itallie, 1988), would be a better measurement as the research is 16 years ahead and a better indicator of health risk.
posted by glennmatthew 3 years and 8 months ago Link
rixx
I agree that BMI is not the best metric for grading weight, that's why I wanted to include a link to the Wikipedia.

As for the grading, it's less dependent on the nationality and more on the age and gender of a person, which is why I'd consider leaving it out for now. Just return the value with a link to a place where you can see where you stand in regards to your age and gender?
posted by rixx 3 years and 8 months ago Link
glennmatthew
Wikipedia is probably the safest landing page, since the content can be readily updated as needed.

How would you intuitively capture the inputs? Just a simple "bmi 180cm 90kg" or "bmi 6'1" 200lbs"?
posted by glennmatthew 3 years and 8 months ago Link
rixx
Both of these (plus weight in stone) are what I'd be looking for.
posted by rixx 3 years and 7 months ago Link
jkanarek
This doesn't need a source suggestion, it would just be goodie. The problem is that the query might be a little awkward. I would consider having a bmi calculator appear on search of "bmi" and also support the more formed query.
posted by jkanarek Staff3 years and 7 months ago Link
rixx
Wouldn't just "BMI" be a bit broad as a query? It should definitely appear on "BMI calculator" though, I think.
posted by rixx 3 years and 7 months ago Link
Jag
I could imagine something JS based like https://duckduckgo.com/?q=timer&ia=timer which would show two fields for the variables.
posted by Jag Staff3 years and 7 months ago Link
rixx
Exactly what I was thinking about :)
(Except it would pre-enter your search terms if you were searching for a specific weight/height)
posted by rixx 3 years and 7 months ago Link
jkanarek
Image embedding isn't working for me, but a quick sketch is up at
https://www.dropbox.com/s/yeqo3mxopzs1po...

Jag, should we change the status of this since no source is required?
posted by jkanarek Staff3 years and 7 months ago Link
anonymous
I like your mockup, can I work on that?
posted by <hidden> • 3 years and 7 months ago Link
jkanarek
Thanks! Go for it! Are you familiar with the PR and development process?
posted by jkanarek Staff3 years and 7 months ago Link
anonymous
Yes, we're almost done see PR https://github.com/duckduckgo/zeroclicki...
posted by <hidden> • 3 years and 7 months ago Link
jkanarek
Very cool.
posted by jkanarek Staff3 years and 7 months ago Link
cloudclipper
Something similar for calculating target heart rate for exercise would be great, too.
posted by cloudclipper 3 years and 7 months ago Link