How to Calculate Your BMI at Home (With or Without a Calculator)
If you want to know your BMI right now, there are two ways to get it: do the math yourself, or use an online BMI calculator that does it in a few seconds. Both give you the same number — the calculator just saves you from doing the arithmetic. The manual formula BMI = weight (kg) ÷ height (m)² If you're working in pounds and inches instead, the formula is: BMI = (weight in pounds ÷ height in inches²) × 703 Let's walk through an example. Say someone weighs 65 kg and is 1.65 m tall. Square the height: 1.65 × 1.65 = 2.7225. Divide the weight by that: 65 ÷ 2.7225 = 23.87. That's a BMI of roughly 23.9, which falls in the "normal weight" range on the standard chart (18.5–24.9). In pounds and inches, someone weighing 143 lbs at 65 inches tall would calculate it as: (143 ÷ 4225) × 703 = 23.79. Same answer, different units. Why use a calculator instead The math itself isn't hard, but it's easy to make small errors — forgetting to square the height, mixing up kg a...