SeaBagRatio first
The first step compares the waist measurement with height.
A clear second step
Height, waist, and weight are used for the body-fat estimate when needed.
One result, explained
See which step determined the projected within-standards result.
Follow the current measurement flow.
The June 2026 Guide 4 uses height, waist, and weight. It starts with waist-to-height ratio; it does not use an older neck-and-hip tape formula or a weight-only pass.
Enter measurements in inches and pounds using the guide’s measurement and rounding procedures. Height is rounded up to the nearest half-inch, waist down to the nearest half-inch, and weight to the nearest pound. The guide also explains where and how the measurements must be taken.
When the first step passes, the calculator stops there. If it does not, the calculator shows the estimated body-fat percentage and its threshold. A personal estimate does not replace the measurements recorded by a certified CFL or trained ACFL.
Measurements taken at different times of day, after different meals, or with different tape tension can move the numbers more than you expect. For the most useful preview, mirror the official conditions: the same time of day, athletic clothing, the tape level and snug, and the abdomen measurement at the natural waist. Repeat the measurement two or three times and average what you see, then bring the recorded values to your official check-in so the CFL’s numbers are not a surprise.
Official reference
Navy Body Composition Assessment · Guide 4, June 2026 ↗Use the current source and your command’s guidance for official decisions.
Common questions
Do I need neck or hip measurements?
This calculator follows the June 2026 Guide 4 process, using height, waist, and weight rather than the older circumference formula.
Does a failed ratio automatically mean a failed BCA?
No. The result proceeds to the body-composition calculation, which can still produce a within-standards result.
Is this an official BCA record?
No. This is a planning estimate. Your command’s official measurement process and applicable Navy guidance determine the recorded result.