Most BMI calculators online ask for your weight in kilograms and height in centimeters. If you think in feet, inches, and pounds — like most people in the US and UK — you end up doing a unit conversion just to use the calculator.
The BMI calculator at Ultimate Tools accepts imperial units directly: feet, inches, and pounds. No conversion step.
Calculate your BMI in imperial units: BMI Calculator — Feet, Inches, Pounds
The Imperial BMI Formula
For those who want to understand the math:
BMI = (weight in pounds × 703) ÷ (height in inches)²
Example: 5'9" (69 inches), 160 lbs
BMI = (160 × 703) ÷ (69²) = 112,480 ÷ 4,761 = 23.6
The 703 factor is the conversion constant that makes the imperial formula produce the same BMI values as the metric formula.
How to Use the Calculator
- Go to the BMI Calculator
- Select Imperial units
- Enter your height in feet and inches (e.g., 5 ft 9 in)
- Enter your weight in pounds
- Click Calculate — your BMI and category appear instantly
BMI Categories (Same Regardless of Units)
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
These categories are defined by the World Health Organization and apply regardless of whether you used metric or imperial inputs.
BMI Reference: Common Heights and Weights
A quick reference for the normal BMI range (18.5–24.9) in imperial units:
| Height | Normal Weight Range |
|---|---|
| 5'0" | 97 – 127 lbs |
| 5'3" | 107 – 141 lbs |
| 5'6" | 118 – 154 lbs |
| 5'9" | 128 – 168 lbs |
| 6'0" | 140 – 183 lbs |
| 6'3" | 152 – 199 lbs |
What BMI Doesn't Tell You
BMI is a screening tool, not a diagnostic one. Two important limitations:
It doesn't distinguish muscle from fat. A muscular athlete and someone with high body fat can have the same BMI. BMI at 27 means very different things for a competitive cyclist and a sedentary office worker.
It uses the same scale for all body types. Research shows BMI thresholds may underestimate health risk for South Asian and East Asian populations, and overestimate it for Black populations. Some health organisations use adjusted thresholds for different ethnic groups.
Use BMI as a starting point for a conversation with a doctor — not as a definitive health verdict.
Frequently Asked Questions
Is BMI calculated differently for men and women?
No. The standard BMI formula is the same for men and women. Some alternative assessments (like body fat percentage) do differ by sex, but BMI itself doesn't.
What BMI is considered healthy?
18.5 to 24.9 is the standard "normal weight" range. However, athletic individuals with high muscle mass often fall in the "overweight" range (25–29.9) despite having low body fat.
How often should I check my BMI?
BMI is a long-term metric — checking monthly is sufficient. Daily weight fluctuations (water retention, meals) can shift BMI by 0.5–1 point without any meaningful change in body composition.
Does height need to be exact?
Half-inch differences in height produce small BMI changes (typically less than 0.2 BMI points). Being close is sufficient for screening purposes.
Related Tools
- BMI Calculator — metric and imperial, instant result, no account needed
Calculate your BMI without unit conversion: BMI Calculator at Ultimate Tools — enter feet, inches, and pounds directly.
Top comments (0)