Reverse BMI Calculator

How Does a Reverse BMI Calculator Work?

A reverse BMI calculator simply turns the usual BMI formula around. Instead of starting with your weight and height, you start with the BMI you want. Then, by entering your height, the calculator shows the weight that matches your target BMI.

Here’s how it works 

1. You tell the calculator your height.
2. You enter the BMI you’re aiming for.
3. It gives you the weight you would need for that BMI.

That’s it. No confusing charts, no guessing.

For example, if you’re 5’7″ tall and you want a BMI of 22, the reverse BMI calculator will show you that your weight should be about 140 pounds.

The only difference between countries is the units: some people use kilograms and meters (metric), while others use pounds and inches (imperial, with the number 703 in the background math). But the calculator handles that for you — you don’t need to worry.

So in short: enter your numbers, hit calculate, and it instantly shows you the result.

The Formula Behind It

To calculate your target weight:

Weight = BMI target × (Height in meters)²

•     Metric units: Height in meters, weight in kilograms.
•     Imperial units: Weight (lbs) = BMI × (Height in inches)² ÷ 703

This lets readers understand exactly what the calculator is doing without overwhelming them with math.

How to Use Our Reverse BMI Calculator – Step-by-Step Guide

Sometimes tools look complicated until someone shows you the exact steps. The good news is, our Reverse BMI Calculator is simple — anyone can use it in under a minute. Here’s how:

Step 1: Enter Your Target BMI

Type in the BMI number you want to aim for. For example, if you’re aiming for a “normal” weight, you might enter 22 (which sits in the healthy range).

 Beginner tip: If you’re not sure what number to choose, stick with the “normal” BMI range (18.5 – 24.9). Most people start around 21–23 because it’s realistic and healthy without being too strict.

Step 2: Choose Your Units

From the dropdown menu, pick whether you want to use feet & inches or centimeters (cm).

Step 3: Enter Your Height

Add your height in the boxes provided.

Step 4: Click “Calculate Target Weight”

Press the button, and the calculator will instantly show you the weight you need to be at to match your target BMI.

Worked Example:

• Height: 5 feet 6 inches
• Target BMI: 22
• Result: 136.3 lbs

That means if you’re 5’6″ tall and want a BMI of 22, your target weight would be around 136 pounds.

Pro Tip: If you switch between units (kg ↔ lbs, cm ↔ inches), double-check that you’ve entered the right one. It’s a common mistake to mix them up, I’ve done it myself and ended up with a number that made no sense!

Why Would You Use a Reverse BMI Calculator?

Let’s be honest, most of us don’t care about the math, we just want to know what number on the scale makes sense for our body. That’s exactly why a reverse BMI calculator is so handy. Instead of staring at charts, it gives you a clear weight target based on your height and the BMI value you’re aiming for.

People use it for all sorts of reasons:

• Weight loss, gain, or maintenance: If you’re trying to drop a few pounds, add muscle, or simply keep things steady, the calculator helps you see what weight lines up with your goal BMI. You can use our free Treadmill Calorie Calculator alongside this to track calories burned during workouts and see how exercise contributes to your goals.
• Athletes and fitness enthusiasts: Many athletes like to check if their training weight matches a “healthy” range, or if their muscle makes their BMI look higher than it should.
• Patients and doctors: In medical settings, BMI is often used as a quick reference. A reverse calculation makes it easy to figure out whether someone is in the “underweight,” “normal,” “overweight,” or “obese” range.
• Planning surgery or insurance qualifications: Some clinics and insurers require patients to meet a certain BMI before approving procedures, such as weight-loss surgery. A reverse calculator shows exactly what weight you’d need to reach that threshold.

I remember once helping a friend who had to lower his weight before qualifying for a minor surgery. Instead of digging through BMI charts, we plugged his height and target BMI into a reverse calculator. It gave him a number to aim for, which made the whole process a lot less confusing.

So whether it’s for personal fitness, professional guidance, or medical planning, this little tool turns BMI from a vague number into a practical target.

So you’ve typed in your numbers and the reverse BMI calculator gave you a target weight — what does that really mean? The key is to match your result with the BMI categories doctors and health experts use.

According to the World Health Organization (WHO), a BMI of 25 or above is classified as overweight, and a BMI of 30 or above is classified as obesity.

Here’s a BMI Ranges:

Example: If you’re 5’6″ tall and the calculator shows 136 lbs for a BMI of 22, that falls in the “normal” range (18.5–24.9). It means your target weight is considered healthy for your height.

The important part is not just the number, but the context. BMI doesn’t measure body fat directly, so someone muscular might land in “overweight” even though they’re fit. On the other hand, someone in the “normal” range might still need to focus on diet and activity for overall health.

Limitations of Reverse BMI Calculations

It’s easy to think that a single number can tell the whole story about your health, but BMI has limits — and so does the reverse version of it. If you use this calculator, keep these things in mind before taking the result too seriously.

1. It Doesn’t Show What Your Body Is Made Of

The calculator only works with weight and height. It doesn’t look at muscle mass, body fat percentage, or bone density. That means two people with the same BMI could look completely different. For example, a bodybuilder and someone with little muscle might both have a BMI of 27, but their health situations are not the same. To get a clearer picture of body composition, you can also try our free Body Fat Calculator, which shows how much of your weight comes from fat versus muscle.

2. Not the Best for Certain Groups

BMI was built as a general population tool, so it’s less accurate for some people:

• Children and teens: (their bodies are still developing.
• Elderly adults: muscle naturally decreases with age.
• Athletes: extra muscle can “inflate” BMI even if they’re fit.
• Pregnant women: BMI doesn’t account for pregnancy changes.

If you’re in one of these groups, the calculator might give you a number that doesn’t really reflect your health.

3. Screening Tool, Not a Diagnosis

It helps to think of BMI as a screening tool, not a diagnostic test. It can highlight if your weight is in a category like underweight, normal, overweight, or obese, but it doesn’t say whether you’re actually healthy or not. Real health involves many other factors: diet, activity, blood pressure, cholesterol, and family history.

4. Always Pair with Professional Advice

This is the big one. A reverse BMI calculator is helpful for planning and curiosity, but it’s not a substitute for speaking to a doctor, dietitian, or health professional. They can look at the bigger picture and guide you with advice tailored to your body, lifestyle, and medical history.

Disclaimer: Always consult a doctor or dietitian for personalized advice before making changes to your diet, exercise, or health plan

I once set my “goal BMI” too low because I thought that meant I’d be healthier. In reality, it left me feeling tired and weaker during workouts. That’s when I realized BMI was just one piece of the puzzle, not the full picture.

So, while this calculator can be a great starting point, treat the result as a guide, not a verdict. Your body is more complex  and valuable than one number on a chart.

Reverse BMI vs. Other Health Metrics

A reverse BMI calculator is useful, but it’s only one way of looking at health. Other tools measure different things, and knowing how they compare helps you decide when to use each.

Reverse BMI vs. BMI

BMI is the traditional way of checking weight in relation to height — you enter your weight and height, and it tells you if you fall into underweight, normal, overweight, or obese ranges. Reverse BMI flips this around. Instead of asking “what’s my BMI?”, it asks “what should my weight be if I want a specific BMI?” This makes reverse BMI more goal-oriented, while standard BMI is more about assessment. And just like with our Chronological Age Calculator, it shows how simple numbers can provide clear insights into more complex health topics.

Reverse BMI vs. BMR (Basal Metabolic Rate)

Reverse BMI focuses on weight and height, giving you a number that matches a target BMI. BMR, on the other hand, is about energy. It tells you how many calories your body burns at rest just to keep you alive, things like breathing, circulating blood, and repairing cells. If your main goal is to figure out what weight is “ideal” for your height, reverse BMI is the tool. If you want to understand how many calories you should eat or cut back on each day, then BMR is the better choice.

Reverse BMI vs. TDEE (Total Daily Energy Expenditure)

Reverse BMI is simple: height, weight, and a BMI value. TDEE goes deeper by looking at how active you are during the day. It calculates the calories you burn not just at rest, but also through walking, working out, or even cleaning the house. That makes TDEE very practical for people trying to manage diet and exercise. Reverse BMI sets the target weight. TDEE helps you build the daily routine to reach it.

Reverse BMI vs. Body Fat Percentage

One of the biggest criticisms of BMI is that it doesn’t separate muscle from fat. That’s where body fat percentage comes in. It gives a clearer picture of your body composition, telling you how much of your weight is actually fat. For athletes or people who train regularly, body fat percentage often matters more than BMI because extra muscle can make BMI seem “high” even when health is excellent. Reverse BMI can help you see a general goal, but body fat percentage tells you the real story of what makes up your weight.

Reverse BMI vs. WHR (Waist-to-Hip Ratio)

BMI looks at your weight in total. WHR, or waist-to-hip ratio, focuses on fat distribution, which has a strong link to health risks like heart disease or diabetes. Two people could share the same BMI but have very different WHR values, and the one with more fat stored around the waist may face higher risks. This makes WHR a good tool if you’re concerned about long-term health risks, while reverse BMI is more about target numbers for weight.

Reverse BMI vs. BSA (Body Surface Area)

BSA, or body surface area, is mostly used in hospitals and clinics. Doctors use it to calculate medication dosages or assess organ function. Reverse BMI is designed for the everyday person who wants to know what weight lines up with a healthy BMI. Unless you’re in a medical setting, BSA isn’t something you need to calculate on your own.

When you put all of these side by side, you can see that a reverse BMI calculator is best for simple, goal-setting purposes. But if you’re trying to understand your body’s energy use, fat distribution, or medical needs, other metrics like BMR, TDEE, WHR, and body fat percentage give you a fuller and more accurate picture.

Use a reverse BMI calculator when you want a simple target weight or height goal. But if you’re serious about health, training, or medical planning, combine it with other metrics like BMR, TDEE, body fat %, and WHR for a fuller picture.

Why We Built This Tool

At Intercalculator, we built this tool because we saw how confusing BMI charts can be. A few years ago, one of our team members was trying to get healthier and kept asking, “What weight should I actually aim for if I want a healthy BMI?” Every chart gave a range, but none gave a clear answer. That frustration stuck with us. We realized there needed to be a simple way to flip the formula around, so instead of guessing, people could type in the BMI they wanted and instantly see the weight that matched. That moment of confusion was the spark that led us to create this reverse BMI calculator.

Final thoughts 

Finding your “ideal weight” doesn’t have to feel like guesswork. A reverse BMI calculator takes the mystery out by turning a BMI value into a clear weight or height target you can actually understand. It’s quick, practical, and gives you a number that feels more real than staring at charts.

But numbers only tell part of the story. BMI can be helpful for setting goals, yet it doesn’t capture muscle, body fat, or overall health. That’s why it’s best used as a guide, not a final verdict. Pair it with other tools, and most importantly, listen to your body and seek advice from health professionals when needed.

In the end, this calculator is like a starting point on your journey. It can point you toward a healthy range, help you plan, and give you confidence in your progress — but you’re the one who decides what balance of health and wellbeing feels right for you.

Remember, this calculator is a guide, not a verdict. For personalized health advice, always consult a healthcare professional.