How to use Body Fat Estimate Calculator

1. Prepare the required inputs

Estimate adult body fat from height and circumference measurements using a Navy-style body-density equation. Use the units and options beside each field. Results update as inputs change; reset returns to example inputs.

Measurement units: Metric (cm, kg) / Imperial (inches, pounds)
Sex used by the formula: Male / Female
Height (cm / inches): minimum 1, maximum 300
Neck circumference (cm / inches): minimum 1, maximum 200
Waist / abdomen circumference (cm / inches): minimum 1, maximum 300
Hip circumference (female formula; cm / inches): minimum 1, maximum 300

2. Try a worked example

Male measurements of height 170 cm, neck 35 cm and waist 85 cm give approximately 20.3%.

3. Understand the calculation

Male density = 1.0324 − 0.19077 log₁₀(waist − neck) + 0.15456 log₁₀(height). Female density = 1.29579 − 0.35004 log₁₀(waist + hip − neck) + 0.221 log₁₀(height). Body fat % = 495 ÷ density − 450; all dimensions in cm.

4. Read the assumptions

Adult circumference estimate, not a clinical measurement. Measure consistently; invalid or out-of-model measurements produce no result. This is not a current military fitness assessment.

5. Check and compare results

Match entered values to their labels and units. Review output labels alongside the assumptions, then change one input at a time. A currency selector changes display labels without converting amounts. Use the available save or copy actions and retain the input values so the estimate can be reproduced.

6. Fix an invalid input

Complete required fields and respect the listed bounds. Check date order, age relationships and mode-specific requirements where relevant; the error message identifies invalid combinations. Reset to example inputs to recover. A valid calculation applies to its stated model and does not verify a real-world outcome.