How to Calculate Body Fat Percentage — 5 Methods Explained (Australia)

By Weight Loss Percentage Editorial Team  |  Reviewed by Dr. Sarah Jenkins, RD  |  July 2026  |  10 min read

Body fat percentage is one of the most important metrics for tracking your health and fitness. Unlike scale weight or BMI, it tells you exactly how much of your body is fat tissue versus muscle, bone, and water. In this guide, we cover 5 ways to calculate body fat percentage — from free home methods to clinical gold standards.

Method 1: US Navy Circumference Method (Best Free Method)

The US Navy method is the most practical and accurate way to calculate body fat percentage at home. It uses a tape measure — no equipment purchase needed — and is accurate to within 3-4% of DEXA scans. This is the method used by the US military for mandatory fitness standards testing.

What You Need

• A flexible tape measure
• For men: waist and neck measurements (in inches)
• For women: waist, hips, and neck measurements (in inches)
• Your height in inches

How to Measure (Tips for Accuracy)

• Waist: Measure at the narrowest point (typically at the navel for men, smallest point for women). Exhale normally — do not suck in.
• Neck: Measure just below the larynx (Adam's apple), tilting the tape slightly downward at the front.
• Hips (women only): Measure at the widest point, typically across the largest part of the buttocks.
• Take 2-3 measurements and use the average for accuracy.

The US Navy Body Fat Formula

For Men:

For Women:

This formula involves logarithms — use our free Body Fat Percentage Calculator to get your result instantly.

Example (Men): Waist = 34", Neck = 15", Height = 70"
Body Fat % = 495 ÷ (1.0324 − 0.19077 × log(19) + 0.15456 × log(70)) − 450 ≈ 17.8% (Fitness category)

Method 2: BMI-Based Body Fat Estimation

If you only have your BMI, you can estimate body fat percentage using the Deurenberg formula. This is less accurate than circumference methods (±5-6%) but works if you have no tape measure.

Example: A 35-year-old woman with BMI 24:
Body Fat % = (1.20 × 24) + (0.23 × 35) − (10.8 × 0) − 5.4 = 28.8 + 8.05 − 0 − 5.4 = 31.45% (Acceptable range)

Get your BMI first with our BMI Calculator for Women and Men.

Method 3: Skinfold Calipers

Skinfold calipers measure the thickness of subcutaneous fat at specific body sites. A trained technician pinches fat at multiple points (typically 3, 4, or 7 sites) and enters the values into a formula.

• Accuracy: ±3-5% (highly dependent on technician skill)
• Cost: $10-30 for calipers; professional testing $20-50
• Pros: Inexpensive, portable, widely used in fitness testing
• Cons: Difficult to self-administer accurately; results vary between technicians

Popular formulas include Jackson-Pollock 3-site (chest, abdomen, thigh for men; triceps, suprailiac, thigh for women) and Jackson-Pollock 7-site for higher accuracy.

Method 4: Bioelectrical Impedance Analysis (BIA)

BIA scales and handheld devices send a small electrical current through your body. Since fat and muscle conduct electricity differently, the device estimates body composition.

• Accuracy: ±3-8% (varies significantly with hydration, time of day, food intake)
• Cost: $20-200 for consumer scales; $1,000+ for clinical devices
• Pros: Extremely convenient — built into many bathroom scales
• Cons: Wide accuracy range; dehydration, recent meals, and exercise significantly affect results

Tip for BIA accuracy: Always measure at the same time of day (first thing in the morning, after using the bathroom, before eating or drinking) for consistent comparative readings.

Method 5: DEXA Scan (Gold Standard)

Dual-Energy X-ray Absorptiometry (DEXA) is the clinical gold standard for body composition measurement. It distinguishes fat mass, lean mass, and bone mineral density with exceptional precision.

• Accuracy: ±1-2%
• Cost: $50-150 at imaging clinics and some university labs
• Pros: Most accurate method; also measures bone density and regional fat distribution
• Cons: Requires appointment, travel to a clinic, and cost. Minimal radiation exposure (less than a dental X-ray)

DEXA is ideal for an accurate baseline measurement once or twice per year. Use a free method like the US Navy formula for monthly tracking between DEXA scans.

Method Comparison

Healthy Body Fat Percentage Ranges

How to Lower Your Body Fat Percentage

Once you know your body fat percentage, here is how to lower it:

1. Create a moderate calorie deficit (300-500 cal/day) — Use our weight loss calculator for your personalized target
2. Hit 0.7-1.0g protein per pound of body weight — Use our protein calculator
3. Resistance train 3-4x per week — Preserves muscle while losing fat
4. Track progress every 4-6 weeks — Use our body fat percentage calculator

Frequently Asked Questions