The U.S. Navy body-fat method estimates body fat from tape measurements (waist, neck, height) using a log-based formula — no calipers needed, just a tape and Excel.
The example
Waist 36, neck 16, height 70 in.
| A | B | |
|---|---|---|
| 1 | Item | Value |
| 2 | Measurements (in) | — |
| 3 | Body fat | → ~13% |
The formula
The formula:
How it works
How it works:
- Measure waist, neck, and height in inches (the women’s formula adds hip).
- The formula uses
LOG10on (waist − neck) and height. - It returns an estimated body-fat percentage — multiply by weight for fat mass.
- Consistent measuring technique matters more than the formula’s precision.
Educational use only. These are general Excel formulas for learning spreadsheet techniques — estimates only, not training, medical, or nutrition advice. Individual results vary; consult a qualified professional before acting on them.
Try it: interactive demo
Waist, neck, height (inches) — men’s formula.
Variations
Fat mass
From the percentage:
Lean mass
The rest:
Women’s formula
Adds hip:
Pitfalls & errors
Inches. The constants assume inches; convert cm first.
Men vs women. Use the correct formula — the women’s adds hip.
Estimate only. Tape methods approximate; technique drives consistency.
Practice workbook
Frequently asked questions
How do I estimate body fat in Excel?
What's the women's formula?
How do I get fat and lean mass?
Stop fighting formulas. Learn them in a day.
This recipe is one of hundreds of real-world formulas we teach. Our Excel Formulas & Functions class covers lookups, logic, text, and dynamic arrays hands-on — live in Dallas–Fort Worth, Houston, Austin, Oklahoma City, Denver, or online.
See the Formulas & Functions Class