How to Calculate BMI in Pounds and Feet
Use this premium BMI calculator to find your body mass index from weight in pounds and height in feet and inches. Enter your measurements, click calculate, and instantly see your BMI, category, healthy weight range, and a visual chart that places your result against standard adult BMI bands.
BMI Calculator
For adults, the standard formula is BMI = 703 × weight in pounds ÷ height in inches squared.
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Enter your measurements and click Calculate BMI to see your result.
Expert Guide: How to Calculate BMI in Pounds and Feet
Body mass index, usually shortened to BMI, is one of the most widely used screening tools for assessing whether an adult falls into a weight category that may be associated with health risk. If you are searching for how to calculate BMI in pounds and feet, you are looking for the U.S. customary version of the formula, which uses pounds for weight and feet plus inches for height. The process is straightforward once you know the exact steps. In this guide, you will learn the formula, how to do the math manually, how to interpret the result, and when BMI is useful and when it has limits.
BMI is not a direct measurement of body fat. Instead, it is a ratio that compares your weight to your height. Public health agencies and clinical organizations use BMI because it is simple, inexpensive, and practical for large scale screening. The Centers for Disease Control and Prevention, the National Heart, Lung, and Blood Institute, and major academic medical centers all recognize BMI as a helpful starting point when evaluating weight related health risk in adults.
Key formula: BMI = 703 × weight in pounds ÷ height in inches × height in inches.
Example: If a person weighs 180 pounds and is 5 feet 10 inches tall, the total height is 70 inches. BMI = 703 × 180 ÷ 70² = 25.8.
Why the formula uses 703
The original BMI formula was created for metric units:
- BMI = weight in kilograms ÷ height in meters squared
Because many people in the United States measure weight in pounds and height in feet and inches, the formula includes a conversion factor of 703. That number adjusts the equation so your answer matches the metric version. Without 703, the result would not be scaled correctly.
Step by step: how to calculate BMI in pounds and feet
- Measure your weight in pounds. For the best reading, weigh yourself on a reliable scale, ideally at a similar time of day each time you check.
- Convert your height to total inches. Multiply the number of feet by 12, then add the remaining inches. For example, 5 feet 7 inches becomes 67 total inches.
- Square your height in inches. Multiply your total inches by itself. If your height is 67 inches, then 67 × 67 = 4,489.
- Multiply your weight by 703. If you weigh 150 pounds, then 150 × 703 = 105,450.
- Divide by your height squared. 105,450 ÷ 4,489 = 23.5. That is your BMI.
Manual BMI examples using pounds and feet
Here are a few common examples to make the formula easier to remember:
- Example 1: 140 pounds, 5 feet 4 inches. Height in inches = 64. BMI = 703 × 140 ÷ 64² = 24.0.
- Example 2: 175 pounds, 5 feet 9 inches. Height in inches = 69. BMI = 703 × 175 ÷ 69² = 25.8.
- Example 3: 220 pounds, 6 feet 0 inches. Height in inches = 72. BMI = 703 × 220 ÷ 72² = 29.8.
When you understand these examples, the process becomes very fast. You can calculate BMI on paper, on a calculator, in a spreadsheet, or by using the interactive tool on this page.
Adult BMI categories
For most adults age 20 and older, standard BMI categories are interpreted as follows. These ranges are commonly cited by U.S. public health sources and are used in many clinics and wellness programs.
| BMI range | Weight category | General interpretation |
|---|---|---|
| Below 18.5 | Underweight | May indicate inadequate body weight for height and may merit a clinical review. |
| 18.5 to 24.9 | Healthy weight | Often associated with the lowest average risk range in population screening. |
| 25.0 to 29.9 | Overweight | May be associated with increased cardiometabolic risk in some adults. |
| 30.0 and above | Obesity | Associated with higher risk for several chronic conditions at the population level. |
How to convert feet and inches correctly
A very common mistake is using feet only, instead of total inches. BMI requires height in inches when you use pounds. Here is the conversion:
- 5 feet 0 inches = 60 inches
- 5 feet 5 inches = 65 inches
- 5 feet 10 inches = 70 inches
- 6 feet 2 inches = 74 inches
If you skip this step or forget to square the height, the answer will be wrong. Total inches and height squared are both essential.
What your BMI can tell you, and what it cannot
BMI is useful because it is a quick screening tool. It helps identify whether a person may have weight related health risk. For example, higher BMI categories tend to be linked with greater average risk of conditions such as high blood pressure, type 2 diabetes, coronary heart disease, sleep apnea, and some cancers. Lower than expected BMI can also be relevant in situations involving inadequate nutrition, frailty, or certain illnesses.
At the same time, BMI has limitations. It does not directly measure body fat percentage, muscle mass, bone density, or fat distribution. Two people can have the same BMI and very different body composition. A muscular athlete may have a BMI in the overweight range without having excess body fat. An older adult may have a normal BMI but still have low muscle mass and higher body fat. That is why clinicians often interpret BMI together with waist circumference, blood pressure, lab markers, physical activity, medical history, and family history.
Comparison table: U.S. adult obesity statistics
One reason BMI remains important is that it allows large population studies to compare weight related risk across groups. According to the CDC, age adjusted prevalence of obesity among U.S. adults was 41.9% in the period from 2017 through March 2020. The burden is not evenly distributed across age groups.
| Adult group | Obesity prevalence | Source context |
|---|---|---|
| All U.S. adults, age adjusted | 41.9% | CDC estimate for 2017 through March 2020 |
| Adults ages 20 to 39 | 39.8% | CDC estimate for 2017 through March 2020 |
| Adults ages 40 to 59 | 44.3% | CDC estimate for 2017 through March 2020 |
| Adults ages 60 and older | 41.5% | CDC estimate for 2017 through March 2020 |
These numbers help explain why BMI is still widely used in public health. Even though BMI is not a perfect measure of individual body composition, it is a very effective way to analyze trends in large groups and identify areas where prevention and treatment may be needed.
How to estimate a healthy weight range from your height
Once you know your height, you can reverse the formula to estimate what body weight corresponds to a BMI in the healthy range of 18.5 to 24.9. This can be useful if you want to set a practical target range. The formula is:
- Weight in pounds = BMI target × height in inches squared ÷ 703
Suppose you are 5 feet 8 inches tall. Your height is 68 inches, and 68² = 4,624.
- Low end of healthy range: 18.5 × 4,624 ÷ 703 = about 122 pounds
- High end of healthy range: 24.9 × 4,624 ÷ 703 = about 164 pounds
This estimate should not replace clinical advice. A suitable weight target depends on context such as age, strength, medical conditions, body composition, medications, and goals.
Common mistakes when calculating BMI in pounds and feet
- Forgetting to convert feet to inches. If you enter 5 instead of 60 for 5 feet, the result becomes meaningless.
- Not squaring the height. Height must be multiplied by itself.
- Leaving out the 703 factor. That constant is required for pounds and inches.
- Mixing metric and U.S. units. Do not use pounds with meters unless you convert properly first.
- Applying adult cutoffs to children and teens. BMI interpretation for people ages 2 through 19 is based on age and sex specific percentiles, not the standard adult ranges.
Special cases where BMI deserves extra caution
Some groups need more individualized interpretation. Athletes and highly muscular people may have a higher BMI without excess body fat. Pregnant individuals should not use standard BMI as the only guide to health status. Older adults may lose muscle while maintaining similar body weight, so BMI alone can miss changes in body composition. People from different ethnic backgrounds may also have different risk patterns at the same BMI. These issues do not make BMI useless, but they do mean that BMI should be treated as one screening tool among several.
Authoritative sources for BMI guidance
If you want to verify formulas or review public health guidance, these sources are especially useful:
- CDC adult BMI guidance and calculator
- National Heart, Lung, and Blood Institute BMI resources
- Harvard T.H. Chan School of Public Health explanation of BMI
When to talk with a healthcare professional
You should consider discussing your BMI with a qualified healthcare professional if your result falls below 18.5 or above 25, if your weight has changed significantly over a short period, or if you have risk factors such as diabetes, high blood pressure, elevated cholesterol, sleep problems, or limited physical activity. A clinician can add context through blood tests, waist measurement, medication review, nutrition assessment, and personalized recommendations.
Bottom line
If you want to know how to calculate BMI in pounds and feet, the most important steps are to convert height into total inches, square that height, multiply weight in pounds by 703, and divide by height squared. The formula is simple, fast, and useful for adult screening. Still, BMI works best when combined with the bigger picture, including body composition, fitness level, waist size, and overall health markers. Use the calculator above for a quick result, then use your result wisely as part of a broader health assessment.