BMIzr Support

We think BMIzr is the best BMI calculator in the world: easy to understand and easy to use. But then we’ve been working on it a long time. Here’s a rundown.

What is BMI?
Body Mass Index (BMI) is a ratio between a person’s weight and height, computed as follows:

BMI = ( weight in kilograms ) / (height in meters, squared)

It is used as one indicator of physical health. The “ideal” range of values is between 18.5 and 25. A value over 30 is typically considered “obese” but such assessment is best left to a health professional who will consider many factors before making a diagnosis.

The Wikipedia article is fascinating!

How do I work this thing?
There’s no keypad in BMIzr, it’s all about touch. You can directly manipulate the height and weight sliders, or you can drag a finger or thumb across the avatar to adjust both at the same time. You can also pinch/spread to make faster changes.

Note that operating with your thumb can free up your other hand for writing. To make things even easier, you can use either of two mirror-image layouts. Fast, easy, and even fun to use!

Pfft! I can calculate this myself!
Yes, you can. BMIzr just makes a simple calculation even easier, and reduces the chances of flubbing the result by using the wrong units or the wrong conversion factors somewhere. We’re big fans of DIY here, but we’re even bigger fans of foolproof tools that help us work faster with fewer mistakes.

Aren’t there already enough BMI calculators in the App Store?
It breaks our hearts to see people using a cruddy application with a lousy interface. Sadly, just about every BMI-calculating app we’ve looked at focuses on the calculation itself, with little regard for the way you input the values. We took the opposite approach: make it as easy as possible to set height and weight, and give the BMI all the time.

BMIzr delights us, and we hope it delights you.

Why can’t I track my BMI day to day?
There are applications that do this, but we find their value to be questionable. If this feature is important to you, BMIzr probably isn’t what you’re looking for. BMIzr was designed mainly for health professionals, such as dietitians, who must calculate BMI values for many different people every day.

Our research tells us that an individual’s BMI changes very slowly over time–your height is unlikely to change very quickly, if at all–and day-to-day graphs are basically flat. If short-term changes are important to you, we recommend you track your weight, which can vary more widely over a short period of time. There is no shortage of applications to help with this.

It says my BMI is high. I’m not fat, I’m muscular!
We believe you. Like many diagnostic tools, the BMI calculation has shortcomings, and this is one of them.

Remember that BMI is chiefly used as a statistical measure of an individual with respect to the population at large. You may be an edge case, a bit outside of statistical norms.

BMI values above 25 are considered high, but not definitively obese, and a muscular build could present an exception. It is unlikely that a person would have a BMI above 30 and not be obese, but don’t take our word for it. If you’re at all concerned about your weight, please consult a health professional!

What range does BMIzr cover?
At 8’11″ and 485 lbs., all-time tallest man Robert Wadlow scores a BMI of 29.8. Shortest man Gul Mohammed racks up a BMI of 52.3 with a height of 57.0cm and weight of 17 kgs.

A Bigfoot sighting in 1941 estimates his height at 7’6″, and weight at about 500 lbs. His BMI? 43.5!

I wish BMIzr could also _______.
Then please tell us about it!