# How to calculate BMI?

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I am 5'10" and weigh 170 pounds. what is my BMI?? How do u convert to pounds? Lastly, how many pounds overweight does it take to be considered obese....not fat?

Posted Thu, 27 Mar 2014
in Weight

Answered by Dr. Prasad 27 minutes later

Brief Answer:
BMI is around 24.3
Detailed Answer:
Hi,
Based on your anthropometric measurements, your BMI stands at around 24.3 which by definition falls just under normal limits. You will be termed obese if you put on 40 pounds more; at 210 pounds your BMI will be above 30.
In terms of pounds, the following formula apply for BMI calculations:
1. Weight in pounds X 0.454 / Height in meter square
2. Weight in pounds X 703 / Height in inch square
Hope this helps. Let me know if you need clarifications.
Regards

Follow-up: How to calculate BMI? 27 minutes later

regarding calculating my BMI......i am 5'10'' 170 pounds......i take 170 times, which is 77.18.....then divide height.....i only know feet and inches. please show your work how to convert height in square inch and height in square meter. lets say i am 5'5'' and 150 pounds......show your work how to calculate the BMI. I live in the USA.
ihere an exact number of pounds overweight to be considered obese?? Is it 100 over, does it depend? If it depends, teach me how and why.
my BMI is 24.3.....is that good?? what is a healthy BMI?? what is an unhealthy BMI?? the higher......is worse & the lower is better. correct?

Answered by Dr. Prasad 33 minutes later

Brief Answer:
Obesity number is again height dependent...
Detailed Answer:
I stopped practicing mathematics long time ago; but I'll try and do the calculations here:
1. 5'10" is equivalent to 177.8 cm = 1.77 metres = 70 inches
2. Accordingly, the BMI is equal to
170 X 0.454 / (1.77 X 1.77) or 170 X 703 / (70 X 70)
which is roughly equal to 24.39
The first formula is 0.454 times 170 lbs divided by square of 1.77 metres. The later is 703 times 170 lbs divided by square of 70 inches.
For some one who is 5'5" which is equivalent to 65 inches and 1.65metres. The same calculation brings BMI to 24.95
150 X 0.454 / (1.65 X 1.65) or 150 X 703 / (65X65)
These calculations should make it clear that BMI values are not affected by weight alone. It is directly proportional to weight and inversely proportional to height.
BMI of above 30 is considered as obese. It's not based on weight alone. Accordingly an individual who is 5"10" weight of 210 lbs will make him obese. 180lbs and more weight will make an individual of 5'5" height obese.
Hope this suffices. Feel free to write back for clarifications.
Regards

Follow-up: How to calculate BMI? 1 hour later

150 X 0.454 / (1.65 X 1.65) or 150 X 703 / (65X65)
170 X 0.454 / (1.77 X 1.77) or 170 X 703 / (70 X 70)
focusing on the 2nd way....the 1 where you divide (65x65) & (70x70).....where does the 703 come from? or is that just part of the formula?

Answered by Dr. Prasad 15 minutes later

Brief Answer:
Conversion factor...
Detailed Answer:
703 is the unit of conversion if you need to convert kg/metre square to lbs/inch square. If you do the calculations you would get this number.
0.454 kg equals 1lbs and 0.0254 metres equal 1inch.
Accordingly 0.454/(0.0254 X 0.0254) is roughly equal to 703.
If you don't like mathematics, you need not ponder on these numbers. You can remember that BMI has two formulas
1. Weight in kg / Height in metre square
2. Weigh in pounds X 703 / Height in inch square
Hope this helps.
Regards

Follow-up: How to calculate BMI? 9 minutes later

i think i got it.....lets say someone is 6'6'' & 250 pounds.....i would put
250x703/ (78x78) so the BMI is about 28.89. correct??

Answered by Dr. Prasad 3 hours later

Brief Answer:
You got it absolutely right...
Detailed Answer:
Bingo!!
That's right. Weight of 250 lbs equals 28.89 BMI if the height is 6'6". This is by definition over weight and not obese.
Hope I have sorted your doubt. If you have no more questions please close this discussion.
Regards

The user accepted the expert's answer