Decision tools built for clarity
Body Fat Calculator
Estimate body-fat percentage from circumference measurements using the documented historical equations.
Enter the required values, select the applicable options, and calculate.
This historical screening estimate is not a diagnosis or a current military eligibility decision.
Methodology
Formula or transformation
Applies the selected historical circumference equation after normalizing measurements to centimetres.
Variables
- Height normalized to centimetres
- Neck circumference in centimetres
- Waist circumference in centimetres
- Hip circumference in centimetres
- Estimated body-fat percentage
Units
- Centimetre
- Percent
Rounding policy
The estimate is rounded to the declared percentage scale using half away from zero.
The selected male or female circumference equation normalizes measurements to centimetres and produces a deterministic estimate.
Estimate body-fat percentage from circumference measurements using the documented historical equations.
Reviewed sources
- National Academies / NCBI Bookshelf — Body Composition in the Military Services Reviewed on 2026-09-07
- U.S. Department of War — DoW Instruction 1308.03 body composition program Reviewed on 2026-09-07
Formula review history
-
Initial formula, limitations, and source review.
Reviewed 2026-09-07 for formula version hodgdon-beckett-circumference-v1
Assumptions
- Inputs are interpreted using the displayed units and options.
- The calculation follows the methodology and factors listed in the sources.
Limitations
- Display rounding can hide additional decimal places.
- The calculation cannot add accuracy that is absent from the submitted inputs.
- This historical screening estimate is not a diagnosis or a current military eligibility decision.
Worked example
For a 70-inch male with a 15.5-inch neck and 34-inch waist, the estimate is about 16.46%.
Frequently asked questions
Are the calculations deterministic?
Yes. The same valid inputs and options produce the same canonical result.
Can I use decimal values?
Use decimal values where the displayed input accepts them.