How much weight do I need to lose to reach a healthy BMI?

Multiply your target BMI by your height in metres squared to get your goal weight, then subtract it from your current weight. For example, someone 175cm and 90kg has a BMI of about 29.4. To reach a BMI of 24.9 they would weigh about 76.3kg, so roughly 13.7kg to lose.

What is a healthy BMI range?

A BMI of 18.5 to 24.9 is generally classed as the healthy range for adults, with 25 to 29.9 overweight and 30 or more obese. For a height of 175cm that healthy range is about 56.7kg to 76.3kg. Ranges can differ for some ethnic groups, so use them as a guide.

Is BMI a good measure of healthy weight?

BMI is a quick screen based only on height and weight, so it does not account for muscle, frame or where fat is carried. A very muscular person can read as overweight while being lean. Use BMI alongside waist measurement and other checks, and get personal advice from a health professional.

BMI Weight Loss Calculator

This BMI weight loss calculator turns a target BMI into a real weight goal, so instead of an abstract number you get the kilograms you would need to lose to reach it. Enter your height, your current weight and the BMI you are aiming for, and the calculator shows your current BMI, the goal weight that matches your target BMI, and how much weight sits between the two. It also gives the full healthy weight range for your height, based on the standard BMI band of 18.5 to 24.9, so you can see the lightest and heaviest you can be while still reading as a healthy weight. That makes it easy to set a sensible goal: many people aim for the top of the healthy range first, which is a smaller and more achievable step than the middle. The tool is useful for planning a weight loss journey, checking progress against a target, or simply understanding what a BMI figure means on the bathroom scales. Bear in mind that BMI is a broad screen that ignores muscle, frame and body composition, and that healthy ranges can differ between ethnic groups. Use it as a starting guide and talk to a health professional for advice tailored to you. This tool is general information only and not medical advice.

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Height (cm)

Current weight (kg)

Target BMI

13.7 kg

weight to lose to reach your target BMI

Current BMI29.4

Goal weight76.3 kg

Healthy range56.7 to 76.3 kg

At 175 cm and 90 kg your BMI is 29.4. To reach a BMI of 24.9 you would weigh 76.3 kg, so about 13.7 kg to lose. A healthy weight for your height is 56.7 to 76.3 kg.

BMI is a broad screen and ignores muscle and body composition. Healthy ranges can differ between ethnic groups. General information only, not medical advice.

How it works

BMI is your weight in kilograms divided by your height in metres squared. To flip it around, the calculator multiplies your target BMI by your height squared to find the weight that would give that BMI, which is your goal weight. The difference between your current weight and that goal weight is the amount to lose. The healthy weight range comes from applying the same step to the standard BMI band, using 18.5 for the lightest healthy weight and 24.9 for the heaviest, both scaled to your height.

Worked example

Say you are 175 cm tall, weigh 90 kg, and want to reach a BMI of 24.9. Your height in metres is 1.75, and squared that is 3.0625. Your current BMI is 90 divided by 3.0625, which is about 29.4. Your goal weight is 24.9 times 3.0625, or about 76.3 kg, so you would need to lose roughly 13.7 kg. Applying 18.5 and 24.9 to the same height gives a healthy range of about 56.7 kg to 76.3 kg, so reaching your target lands you right at the top of that range.

Related calculators

BMI Calculator: your BMI and category.
Ideal Weight Calculator: healthy weight for your height.
Calorie Calculator: daily calories to lose weight.
TDEE Calculator: total daily energy use.
Body Fat Calculator: estimate body fat percentage.

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