Which metric should I track for fat loss?

For most people, waist-to-height ratio is the best weekly metric for fat loss because it reflects changes in abdominal size. If you can measure neck and hip consistently, the Navy body fat estimate can also be useful for trends, but focus on consistency over precision.

Why does BMI misclassify muscular people?

BMI is based on height and weight only, so higher muscle mass can increase BMI even when body fat is low. If you lift, combine a BMI calculator result with waist-to-height ratio to see whether weight changes are happening around the waist.

How often should I measure waist?

Once per week is enough for most people. Measure at the same time of day, in the same location (usually at the navel), and with the same tape tension. That consistency makes the waist to height ratio calculator result more comparable week to week.

Free toolWaist to height ratio calculatorBMI calculatorNavy body fat calculatorUS + metric

Which Body Metric Should You Track?

Use this body composition calculator to compare three simple metrics: a waist to height ratio calculator result (WHtR), a BMI calculator result, and a navy body fat calculator estimate. Enter your height, weight, and waist, then add neck and hip for the Navy estimate (hip is required for females). US units are the default, with a metric toggle. Estimates only. Not medical advice. See Methods & assumptions for formulas and interpretation.

Results

Waist-to-height, BMI, and Navy body fat.

Enter height, weight, and waist, then click Calculate to see your waist-to-height ratio, BMI, and (optionally) Navy body fat estimate.

Decision helper

Add your measurements to get a recommendation.

Enter height, weight, and waist to see which metric is the best weekly target.

Estimates only. Not medical advice.

Methods & assumptions

This variant focuses on Which Body Metric Should You Track?.

This tool compares three common body measurements. It is a body composition calculator, not a medical diagnosis.

Waist-to-height ratio: WHtR = waist / height. Interpretation: < 0.5 lower risk, 0.5 to 0.6 increased risk, > 0.6 higher risk.
BMI: BMI = kg / m². BMI does not separate muscle from fat, so it can misclassify muscular people.
Navy body fat: Uses log10 with measurements in inches. Male: 86.010 * log10(waist - neck) - 70.041 * log10(height) + 36.76. Female: 163.205 * log10(waist + hip - neck) - 97.684 * log10(height) - 78.387. Other: average of male and female formulas.
Measurement locations: waist at the navel, neck just below the larynx, hip at the widest point.
Rounding: WHtR to two decimals; BMI and body fat to one decimal.