Introduction
A normal BMI calculator tells you your BMI when you type in your height and weight. This Reverse BMI Calculator works the other way around. You pick the BMI you want, enter your height, and it tells you the weight you need to hit that number.
That helps if you have a weight goal in mind but do not know what number to aim for. If you are 5 ft 6 in and want a BMI of 22, the tool shows you the exact target weight in both pounds and kilograms.
You can also add your current weight. The calculator then shows how many pounds or kilos you need to lose or gain to reach your goal. It tells you if your target BMI is underweight, normal, overweight, or obese, and shows the full math step by step so you can see how the answer was found.
BMI is a simple screening tool. It does not measure muscle, bone, or body fat, so athletes and older adults may get results that do not match their real health. Talk to a doctor before setting a weight goal.
How to use our Reverse BMI Calculator
Enter your height and the BMI you want to hit. The Reverse BMI Calculator then shows your target weight in both pounds and kilograms, your BMI category, and how much weight you need to lose or gain.
Unit System: Pick Imperial (ft, in, lbs) or Metric (cm, kg). Your numbers switch over for you, and results still show both units.
Height: Type your height in feet and inches, or in centimeters if you chose Metric. Height must be between 4 ft 0 in and 7 ft 0 in (120 cm to 215 cm).
Height Slider: Drag the slider if you would rather not type. It moves with the boxes above, so both always match.
Target BMI: Enter the BMI you are aiming for, from 15 to 40. A BMI of 18.5 to 24.9 is the normal range, and the tool warns you if your goal sits outside it.1
Current Weight: This one is optional. Add your weight now in lbs or kg, and the calculator tells you how many pounds or kilos you need to lose or gain.
Calculate and Reset: Press Calculate to see your target weight, the step-by-step math, and the chart. Press Reset to clear everything and start again.
What Is a Reverse BMI Calculator?
BMI stands for Body Mass Index. A normal BMI calculator takes your height and weight and gives you a number. A reverse BMI calculator flips that around. You pick the BMI you want, enter your height, and it tells you the weight you would need to hit that BMI. That number is your target weight.
The Math Behind It
The BMI formula is weight in kilograms divided by height in meters squared. To go backward, you multiply instead of divide:
Target weight (kg) = Target BMI × Height (m) × Height (m)
To get pounds, divide the kilograms by 0.45359237. Height is the only body measurement you need, so the answer is the same for everyone of the same height.
BMI Categories
- Underweight (BMI under 18.5)1
- Normal weight (BMI 18.5 to 24.9)1
- Overweight (BMI 25.0 to 29.9)1
- Obese (BMI 30.0 and up)1
The CDC applies adult BMI categories to people age 20 and older, whatever their age, sex, or race.2
Why People Use It
The main reason to use a reverse BMI calculator is to set a weight goal. If your BMI is 28 and you want to reach 23, this tells you the exact weight to aim for. It also shows how many pounds or kilograms you need to lose or gain to get there. A real number is easier to follow than a vague goal.
What BMI Does Not Tell You
BMI only uses height and weight. It cannot tell muscle from fat. A strong athlete can have a high BMI and still be very healthy. An older adult can have a normal BMI but low muscle. BMI also does not show where fat sits on your body, and belly fat carries more health risk than fat on the hips or legs.
So BMI works best as a quick screening tool, not a diagnosis. Waist size, body fat percent, blood pressure, and blood tests give a fuller picture. Talk to a doctor before setting a big weight goal, especially if you are pregnant, under 20, or have a health condition.
Reaching Your Target Weight Safely
MedlinePlus says most people are safest losing half a pound to 1 pound a week, and calls a loss of more than 2 pounds a week rapid weight loss.6 Losing weight faster than that often costs you muscle and is harder to keep off. Steady changes to food, movement, and sleep beat quick fixes almost every time.