Most people use BMI the normal way: enter height and weight, get a number. Sometimes you need the opposite. If you know the BMI you want to reach, you can work backwards to find the weight that matches it for your height. That is what a reverse BMI calculation does.
The reverse BMI formula
BMI is weight divided by height squared. Rearranging it gives the target weight:
Metric: Target weight (kg) = Target BMI × Height (m)²
Imperial: Target weight (lb) = Target BMI × Height (in)² ÷ 703
The 703 in the imperial version converts pounds and inches into the same units used by the metric formula.
Example 1: Metric
Height 1.75 m, target BMI 22.
- Square the height: 1.75 × 1.75 = 3.0625.
- Multiply by the target BMI: 22 × 3.0625 = 67.375.
- Target weight ≈ 67.4 kg.
Example 2: Imperial
Height 5 ft 9 in (69 inches), target BMI 22.
- Square the height in inches: 69 × 69 = 4,761.
- Multiply by the target BMI: 22 × 4,761 = 104,742.
- Divide by 703: 104,742 ÷ 703 ≈ 149 lb.
Find a weight range instead of one number
For adults, the CDC classes a BMI of 18.5 to 24.9 as the healthy weight range. Running the formula at both ends gives a range for your height. At 1.75 m that is about 56.7 kg to 76.3 kg; at 5 ft 9 in it is about 125 lb to 169 lb.
| Adult BMI category (CDC) | BMI | Weight at 1.75 m |
|---|---|---|
| Underweight | Below 18.5 | Below 56.7 kg |
| Healthy weight | 18.5 to 24.9 | 56.7 – 76.3 kg |
| Overweight | 25 to 29.9 | 76.6 – 91.6 kg |
| Obesity | 30 or higher | 91.9 kg or more |
Weight ranges for each adult BMI category at a height of 1.75 m.
How to choose a sensible target BMI
- A range is more realistic than a single number. Bodies naturally vary by a few kilograms.
- Smaller steps are easier to sustain. Moving from a BMI of 31 to 29 is a meaningful first goal.
- If you are very muscular, BMI may overstate body fat, so a lower target may not be appropriate.
Limits of BMI you should know
BMI is a screening tool, not a diagnosis. It does not measure body fat directly and does not show where fat is stored. It can be less accurate for athletes, older adults and some ethnic groups, and the adult categories do not apply to children and teens, who use age- and sex-specific percentiles. Waist measurement and a check-up with a healthcare professional give a fuller picture.
Healthy weight range by height
Using the adult BMI range of 18.5 to 24.9, these are the weights that fall in the healthy range at common heights:
| Height | Weight for BMI 18.5 | Weight for BMI 24.9 |
|---|---|---|
| 1.60 m (5 ft 3 in) | 47.4 kg (104 lb) | 63.7 kg (140 lb) |
| 1.70 m (5 ft 7 in) | 53.5 kg (118 lb) | 72.0 kg (159 lb) |
| 1.80 m (5 ft 11 in) | 59.9 kg (132 lb) | 80.7 kg (178 lb) |
| 1.90 m (6 ft 3 in) | 66.8 kg (147 lb) | 89.9 kg (198 lb) |
BMI doesn’t show where you carry weight. For a fuller picture, add a waist measurement – see alternatives to BMI.
Calculate it in seconds
The reverse BMI calculator does the squaring and unit conversion for you and shows the full healthy range for your height. For daily calorie needs to reach that weight, see the TDEE calculator.
Important
Important: This article is general educational information, not medical or nutrition advice. Talk to a doctor or registered dietitian before changing your diet, especially if you are pregnant, under 18, or have a medical condition.
Frequently asked questions
Multiply your target BMI by your height in metres squared. For example, BMI 22 at 1.75 m is 22 × 3.0625 = 67.4 kg. In pounds, multiply BMI by height in inches squared and divide by 703.
It depends on height. At 1.75 m it is about 67.4 kg; at 5 ft 9 in it is about 149 lb. Use the formula or the reverse BMI calculator for your exact height.
A BMI of 22 sits in the middle of the adult healthy range (18.5 to 24.9), but there is no single ideal number. A healthcare professional can help you set a personal target.
No. Children and teens are assessed with BMI-for-age percentiles, so the adult formula and categories should not be used for them.
Related calculators
Related articles
- Alternatives to BMI: Waist, Ratios and Body Fat
- Reverse BMI vs Ideal Body Weight: Which Should You Use?
- TDEE vs BMR: What’s the Difference and Which to Use?
