How to use this calculator
Enter your height using either inches or centimeters. Then either select a BMI category from the quick-select buttons or type in a specific target BMI. Choose whether you want your result in pounds or kilograms. Hit calculate and you will instantly see the exact weight you need to reach that BMI.
What is a reverse BMI calculator?
A standard BMI calculator takes your height and weight and tells you your current BMI. A reverse BMI calculator works the other way — you enter your height and a target BMI, and it tells you exactly what weight you need to be to hit that BMI. It is one of the most practical tools for setting a concrete, measurable weight loss or weight gain goal.
BMI categories explained
| BMI Range | Category | What it means |
|---|---|---|
| Below 18.5 | Underweight | Below healthy weight range |
| 18.5 — 24.9 | Normal weight | Healthy weight range |
| 25.0 — 29.9 | Overweight | Above healthy weight range |
| 30.0 and above | Obese | Significantly above healthy range |
Source: BMI category ranges are based on the CDC adult BMI guidelines and the WHO obesity and overweight fact sheet.
How is the ideal weight calculated?
The formula is straightforward. BMI is defined as weight in kilograms divided by height in meters squared. To reverse this, we simply multiply the target BMI by height in meters squared to get the target weight in kilograms. The calculator then converts to your preferred unit.
Weight (kg) = Target BMI × Height (m)²
// Imperial — weight in lbs, height in inches
Weight (lbs) = Target BMI × Height (in)² ÷ 703
// Reverse — find current BMI from weight and height
BMI = Weight (kg) ÷ Height (m)²
Is BMI a perfect measure?
BMI is a useful starting point but it has limitations. It does not account for muscle mass, bone density, age, or body fat distribution. A very muscular person may have a high BMI without being overweight. A person with low muscle mass may have a normal BMI while still carrying excess body fat. Use BMI as a general guide, not an absolute measure of health.
Important
Not medical advice. BMI is a screening tool and does not diagnose health or directly measure body fat. This calculator is intended for adults and provides an estimate of the weight-to-BMI relationship based on the standard BMI formula — not a recommended goal weight.
- Children and teens: BMI should be interpreted using BMI-for-age percentiles — see CDC or NIH guidance or speak with your clinician.
- Pregnancy and postpartum, athletes or people with high muscle mass, and certain medical conditions can make BMI misleading — talk to a clinician for individualized guidance.
- If you have (or suspect) an eating disorder or are aiming for a very low BMI, please seek professional support before making weight-change plans.
What BMI should I target?
For most adults, a BMI between 18.5 and 24.9 is considered healthy. A target of 21 to 22 sits comfortably in the middle of the healthy range and is a good goal for most people. If you are very athletic or have significant muscle mass, a slightly higher BMI may still be healthy for you.
Frequently asked questions
For most adults, a BMI between 18.5 and 24.9 is considered healthy. A BMI of 21 to 22 is a common and practical target that sits comfortably in the middle of the healthy range.
The calculation itself is mathematically exact — it uses the standard WHO BMI formula in reverse. However, BMI has known limitations as a health metric, so treat the result as a useful goal weight estimate rather than a medically precise target.
BMI categories based on: World Health Organization (WHO) — Obesity and Overweight Fact Sheet.
It depends on your height. For a 5 foot 8 inch person, a BMI of 22 corresponds to approximately 145 lbs. Use the calculator above with your exact height to get a personalized result.
Yes. If you are underweight and want to reach a healthy BMI, simply enter a target BMI of 18.5 or higher and the calculator will show you the weight you need to gain to reach that goal.
The standard BMI scale applies to both men and women equally. However, women naturally carry more body fat than men at the same BMI. Some health professionals use adjusted interpretations, but the standard WHO categories remain the most widely used reference.
A sustainable rate of weight loss is 0.5 to 1 lb per week. Once you know your target weight from this calculator, divide the difference by 0.75 to estimate a realistic number of weeks to reach your goal at a moderate pace.
For someone who is 5 feet 4 inches tall (64 inches / 163 cm), a BMI of 22 corresponds to approximately 128 lbs (58 kg). Use the calculator above with your exact height for a precise result.
For someone who is 5 feet 10 inches tall (70 inches / 178 cm), a BMI of 25 corresponds to approximately 174 lbs (79 kg). This is the upper boundary of the healthy weight range — just at the line between Normal and Overweight.
BMI is calculated purely from height and weight — it does not measure fat directly. Body fat percentage measures the actual proportion of your body that is fat tissue. Two people with the same BMI can have very different body fat percentages depending on how much muscle they carry. BMI is useful as a quick screening tool; body fat percentage gives a more accurate picture of body composition.
Yes. Use the "Find Your BMI" tab on the calculator above. Enter your current height and weight and it will calculate your current BMI instantly and show you where you fall on the BMI range.