Body composition

Circumference Body Fat Calculator

The US Navy method estimates body fat from neck, waist, and (for women) hip circumferences. No calipers, no scale needed.

The US Navy circumference method estimates body fat percentage from height plus neck and waist measurements (and hip for women). It's the standard the US Navy uses for fitness assessments. Accurate to ±3–5% with proper measurement technique.

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Your daily target

· cal/day

Enter your details and click Calculate

  • BMR · cal/day at rest
  • BMI ·  
  • Lean body mass · kg

Pick your goal

Macros at maintenance

30% protein · 40% carbs · 30% fat

Advanced metrics

Numbers are estimates. Eat at your target for 2 to 3 weeks, track weight, and adjust by ±100 cal/day if it does not match your real maintenance. See how accurate is TDEE?

Show advanced metrics 12 metrics · 7 formulas · 2D macro selector · life-stage

All metrics

Calculate above to populate the full metric table.

All 7 BMR formulas (side-by-side)

Mifflin–St Jeor · Harris–Benedict (revised) · Katch–McArdle · Cunningham · Average · Simple multiplier · Custom

TDEE across activity levels

See how much your TDEE changes between sedentary and athlete. Highlighted bar is your current selection.

Macros: 2D selector

Goal × carb-split matrix: Cut / Maintain / Bulk × Low / Moderate / High carb.

Life-stage adjustments

Luteal phase · Pregnancy (T1/T2/T3) · Breastfeeding · Perimenopause · PCOS

How to measure

  • Neck: below the larynx, tape parallel to floor, no slack
  • Waist: at the navel level, exhale gently, no sucking in
  • Hip (women only): widest point of the hips

Take three measurements per site and use the median. Same-time-of-day measurement reduces noise.

Frequently asked questions

How accurate is the Navy method vs. calipers?
For most adults, comparable, within ±1–2% of caliper results. It's less accurate at extreme body fat ranges (very lean or very obese), where circumferences don't scale linearly with fat mass.
Why does the women's formula include hip?
Women typically store more fat in the hips and thighs (gynoid pattern). Including hip circumference accounts for this and improves accuracy for female bodies.
Can I track changes weekly with this method?
Yes, circumferences change slowly enough that weekly measurements show real trends without too much noise. Daily measurement is too sensitive to water weight and gut content.