Ideal Body Weight Calculator

Introduction

The Ideal Body Weight Calculator helps you find a healthy weight range based on your height and gender. Doctors and health experts use ideal body weight formulas to set goals for patients, figure out medication doses, and check overall health. This tool uses well-known formulas like the Devine formula to give you a quick estimate of what your body weight should be. Keep in mind that ideal body weight is just a guide. It does not account for things like muscle mass, bone structure, or body fat percentage. For a closer look at your body composition, you might also try our Lean Body Weight Calculator. Always talk to a doctor before making big changes to your diet or exercise routine.

How to Use Our Ideal Body Weight Calculator

Enter a few basic details about yourself below, and this calculator will estimate your ideal body weight using multiple trusted formulas. It also shows how your current weight compares to a healthy BMI range.

Unit System: Choose between US/Imperial (pounds, feet, and inches) or Metric (kilograms and centimeters). Switching between the two will automatically convert your entered values.

Sex: Select either Male or Female. The ideal body weight formulas use different calculations for each sex, so this choice directly affects your results.

Age: Enter your age in years. The calculator accepts ages between 2 and 80.

Height: Enter your height. If you are using US/Imperial units, type your height in feet and inches. If you are using Metric units, type your height in centimeters. Your height is the most important input because all ideal body weight formulas are based on how tall you are.

Current / Actual Body Weight (optional): Enter your current weight in pounds or kilograms. This field is optional but recommended. When provided, the calculator will show whether your weight falls below, within, or above the healthy BMI range. It will also calculate your Adjusted Body Weight (ABW), which is useful for medication dosing in clinical settings.

After filling in your information, click the "Calculate Ideal Body Weight" button. The calculator will display your ideal weight using the Devine and Robinson formulas, a healthy BMI weight range, a visual bar showing where your current weight falls, a side-by-side formula comparison table, and a bar chart for easy viewing. Click "Reset" at any time to return all fields to their default values.

What Is Ideal Body Weight?

Ideal body weight (IBW) is an estimated weight that is considered healthy for a person based on their height and sex. Doctors, nurses, and pharmacists use IBW to help with things like figuring out the right dose of medicine, setting nutrition goals, and checking overall health. It is not a perfect number for everyone, but it gives a useful starting point. You can also evaluate your body proportions using our Waist to Hip Ratio Calculator, which measures fat distribution rather than total weight.

How Is Ideal Body Weight Calculated?

There are several well-known formulas used to estimate ideal body weight. This calculator uses two of the most common ones:

• Devine Formula (1974): This is the most widely used formula in hospitals and clinics. For males, it starts at 50 kg for a height of 5 feet and adds 2.3 kg for each extra inch. For females, it starts at 45.5 kg and adds 2.3 kg per inch over 5 feet.
• Robinson Formula (1983): This formula works the same way as Devine but uses slightly different numbers. It tends to give a result that is close to the Devine formula but a little bit lower in most cases.

The calculator also shows your healthy BMI range, which is the weight range that gives you a Body Mass Index between 18.5 and 24.9. A BMI in this range is generally considered healthy for most adults.

What Is Adjusted Body Weight?

When a person's actual weight is higher than their ideal body weight, healthcare providers sometimes use a value called Adjusted Body Weight (ABW). This is especially important for calculating correct medication doses for people who are obese. The formula is simple: ABW equals the ideal body weight plus 40% of the difference between the actual weight and the ideal weight. This calculator automatically shows ABW when your current weight is above your ideal weight.

Important Things to Keep in Mind

Ideal body weight formulas have some limits. They were created mainly for adults and do not account for muscle mass, bone density, body frame size, or ethnic differences. A muscular athlete, for example, might weigh more than their calculated IBW and still be perfectly healthy. Athletes and strength trainers may find the FFMI Calculator more useful, as it accounts for lean mass relative to height. These formulas also become less accurate for very short or very tall people.

IBW is best used as a general guide rather than a strict goal. Pairing your ideal body weight results with metrics like your VO2 Max or heart rate zones can give you a more complete picture of your fitness. If you have questions about what a healthy weight looks like for you specifically, talk to your doctor. They can look at the full picture — including your age, activity level, body composition, and medical history — to give you advice that fits your situation.

Frequently Asked Questions

What is the Devine formula for ideal body weight?

The Devine formula (1974) is the most common formula used in hospitals. For males, it is: 50 kg + 2.3 kg for each inch over 5 feet. For females, it is: 45.5 kg + 2.3 kg for each inch over 5 feet. For example, a male who is 5'10" would have an ideal body weight of about 75.3 kg (166 lbs).

What is the difference between the Devine and Robinson formulas?

Both formulas use the same basic approach — they start with a base weight at 5 feet tall and add weight for each extra inch of height. The difference is in the numbers they use. The Robinson formula (1983) uses slightly different starting weights and per-inch values. Robinson usually gives a result that is a little lower than Devine. Doctors use Devine more often, but Robinson is also well-respected.

Why does the calculator ask for my sex?

Ideal body weight formulas give different results for males and females. On average, males have more muscle and bone mass than females at the same height. Because of this, the formulas use higher base weights and sometimes different per-inch values for males compared to females. Selecting the correct sex ensures you get an accurate result.

Is ideal body weight the same as my goal weight?

Not exactly. Ideal body weight is a medical estimate based only on your height and sex. It does not consider your muscle mass, body fat, bone structure, or personal fitness goals. Your goal weight might be higher or lower than your ideal body weight depending on your body type and lifestyle. Use IBW as a helpful reference point, not a strict target.

Why is my current weight field optional?

The calculator can estimate your ideal body weight using just your height and sex. Your current weight is only needed if you want to see how your actual weight compares to the healthy BMI range. Entering it also lets the calculator show your Adjusted Body Weight and a visual bar that shows where you fall relative to the healthy range.

What does Adjusted Body Weight (ABW) mean?

Adjusted Body Weight is a value used mostly in healthcare, especially for medication dosing in people who weigh more than their ideal body weight. The formula is: ABW = IBW + 0.4 × (Actual Weight − IBW). It accounts for the fact that extra body weight includes both fat and lean tissue, so using full actual weight or only ideal weight for dosing could be inaccurate.

Why does the calculator show a healthy BMI range instead of one exact number?

A healthy BMI falls between 18.5 and 24.9. This means there is a range of weights — not just one number — that are considered healthy for your height. Showing a range gives you a more realistic picture of where a healthy weight falls. One single number cannot capture the natural variety in healthy body types.

Can I use this calculator for children?

This calculator accepts ages from 2 to 80, but the Devine and Robinson formulas were designed for adults. For children and teens, ideal weight is usually assessed using growth charts that account for age and development stage. Talk to a pediatrician for the best guidance on a healthy weight for a child.

Does height affect ideal body weight more than age?

Yes. Height is the main factor in all ideal body weight formulas. The Devine and Robinson formulas do not use age at all — they rely entirely on height and sex. Taller people will always have a higher ideal body weight than shorter people of the same sex. Age can affect body composition over time, but it is not part of these specific calculations.

What if I am very short or very tall?

The Devine and Robinson formulas become less accurate at extreme heights. They were developed using data from people of average height ranges. If you are under about 5 feet or over about 6'6", the results may not reflect a truly healthy weight for you. In these cases, looking at the healthy BMI range or talking to a doctor is a better approach.

Why is my ideal body weight different from what I see on other calculators?

Different calculators may use different formulas. Some use the Devine formula, some use Robinson, Miller, or Hamwi. Each formula gives slightly different results. Our calculator shows both Devine and Robinson results side by side along with the healthy BMI range so you can compare and get a fuller picture.

What does the color-coded bar in the results mean?

The color-coded bar shows where your current weight falls compared to the healthy BMI range. Yellow on the left means below the healthy range. Green in the middle means within the healthy range. Red on the right means above the healthy range. A small arrow marker shows your exact position on the bar.

Can switching between US and Metric units change my results?

No. Switching units does not change your results. The calculator automatically converts your entered values when you switch between US/Imperial and Metric. The underlying math stays the same. Only the display format changes — for example, from pounds to kilograms or from feet and inches to centimeters.

Is ideal body weight accurate for athletes or muscular people?

Not always. Ideal body weight formulas do not account for muscle mass. A muscular person or athlete may weigh significantly more than their calculated IBW while being very healthy. If you have a lot of muscle, IBW may underestimate your healthy weight. Body composition measurements or lean body mass calculations are more useful in those cases.