Most BMI calculators online ask for weight in kilograms and height in centimeters. If you think in pounds, feet, and inches — which is most people in the US, UK, and parts of Canada — you're forced to convert units before you can even use the tool.
The BMI Calculator at Ultimate Tools accepts imperial units directly. Enter height in feet and inches, weight in pounds. No conversion step.
The Imperial BMI Formula
For those who want to understand the math:
BMI = (weight in pounds × 703) ÷ (height in inches)²
Example: 5'9" tall, 160 lbs
Height in inches: (5 × 12) + 9 = 69 inches
BMI = (160 × 703) ÷ (69²)
= 112,480 ÷ 4,761
= 23.6
Result: 23.6 — Normal weight range.
The imperial BMI calculator handles the feet-to-inches conversion internally. You enter 5 feet and 9 inches in separate fields — it combines them automatically.
BMI Ranges (WHO Classification)
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
These ranges are identical whether you calculate in imperial or metric — the formula produces the same dimensionless number either way.
How to Use the Imperial BMI Calculator
- Go to the BMI Calculator
- Select Imperial units
- Enter height: feet field and inches field separately (e.g., 5 ft, 9 in)
- Enter weight in pounds
- Click Calculate
Result shows your BMI value, your WHO category, and where you land on the scale.
Reverse BMI: How Much Would I Need to Weigh?
A useful related calculation: given a target BMI, what weight in pounds gets you there at your current height?
Formula:
Target weight (lbs) = Target BMI × (height in inches)² ÷ 703
Example: Target BMI of 22.0 at 5'9" (69 inches):
Weight = 22.0 × (69²) ÷ 703
= 22.0 × 4,761 ÷ 703
= 148.9 lbs
The BMI Calculator includes this reverse calculation — enter your height and a target BMI to get the corresponding weight in pounds. Useful for understanding what a specific BMI number actually means in real weight terms.
BMI at Different Heights — Imperial Reference
| Height | BMI 18.5 (low normal) | BMI 24.9 (high normal) |
|---|---|---|
| 5'0" (60 in) | 95 lbs | 128 lbs |
| 5'4" (64 in) | 108 lbs | 145 lbs |
| 5'7" (67 in) | 118 lbs | 159 lbs |
| 5'9" (69 in) | 125 lbs | 169 lbs |
| 6'0" (72 in) | 136 lbs | 184 lbs |
| 6'2" (74 in) | 144 lbs | 194 lbs |
These are the pound weights that correspond to the lower and upper bounds of the Normal BMI range for each height.
What BMI Doesn't Measure
BMI is a screening tool, not a diagnostic one. Its known limitations:
Muscle mass isn't accounted for. A person with high muscle density may read as "overweight" despite very low body fat. Athletes frequently fall into this category.
Fat distribution is ignored. Waist circumference and waist-to-hip ratio are better predictors of cardiovascular risk than BMI alone.
Same thresholds for all populations. Research suggests lower BMI thresholds (around 23 for "overweight") are more appropriate for East Asian populations.
Age and sex differences. BMI doesn't adjust for age-related muscle loss or differences in typical body composition between sexes.
Use BMI as a starting reference — not a standalone health verdict. A healthcare provider can put the number in context alongside other measurements.
Calculate BMI in imperial units: BMI Calculator — Pounds, Feet, Inches, Free
No account, no ads on results, no data stored.
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