Body Composition
Weight at a chosen BMI
Rearranging the definition gives the weight that lands on a particular index, which is how the healthy range is turned into kilograms.
The Formula
weight = targetBMI x height^2
Rearranging the definition gives the weight that lands on a particular index, which is how the healthy range is turned into kilograms.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| targetBMI | The index you are aiming at | kilograms per square metre | For the healthy band this is 18.5 at the bottom and 25 at the top. |
| m^2 | Height in metres, squared | square metres | For 1.75 m this is 3.0625. |
| weight | Body mass that produces that index | kilograms | At 175 cm the healthy band spans 56.65625 kg to 76.5625 kg. |
What Each Symbol Means
targetBMIkilograms per square metre
The index you are aiming at
For the healthy band this is 18.5 at the bottom and 25 at the top.
m^2square metres
Height in metres, squared
For 1.75 m this is 3.0625.
weightkilograms
Body mass that produces that index
At 175 cm the healthy band spans 56.65625 kg to 76.5625 kg.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate bmi page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate BMI, filed under Health. Every number the guide produces comes from substituting into this one line.