OneTaskBy Tim King · Updated
Body Fat Percentage Calculator
Navy Tape Measure Method, With Fitness Category and Fat Mass
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How the Body Fat Percentage Calculator works
This body fat percentage calculator estimates how much of your weight is fat from a few tape measurements, using the US Navy method. Enter your height, neck and waist (plus hip for women), and it gives your body fat percentage, the fitness category it falls in and, if you add your weight, your fat mass and lean mass.
Body fat percentage says more about health and fitness than weight or BMI alone, because two people of the same weight can carry very different amounts of muscle. Lab methods such as DEXA scans are accurate but costly. The tape-measure method was developed by the US Navy to screen recruits and is usually within 3 to 4 percentage points of a DEXA reading.
How the body fat percentage calculator works
The US Navy formula for men is body fat % = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450, with all measurements in centimetres. For women it is 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.221 × log10(height)) − 450. The result is placed in the American Council on Exercise categories: essential fat, athletes, fitness, average or obese.
First example. A man 180 cm tall with a 38 cm neck and an 85 cm waist has about 16.1% body fat, in the fitness range. At 80 kg that is 12.9 kg of fat and 67.1 kg of lean mass.
Second example. A woman 5'5" tall with a 13 inch neck, a 30 inch waist and 38 inch hips comes out at about 28.3%, in the average range for women.
How many inches should I lose from my waist to drop 1% body fat? For most men about 1 cm (0.4 in) of waist equals roughly 0.8% body fat, as the table shows.
Body fat percentage by waist size for a 178 cm man with a 38 cm neck and a 165 cm woman with a 33 cm neck and 98 cm hips
| Men's waist | Men's body fat | Women's waist | Women's body fat |
|---|---|---|---|
| 70 cm (27.6 in) | 2.8% | 60 cm (23.6 in) | 20.6% |
| 72 cm (28.3 in) | 4.9% | 62 cm (24.4 in) | 21.7% |
| 74 cm (29.1 in) | 6.9% | 64 cm (25.2 in) | 22.8% |
| 76 cm (29.9 in) | 8.8% | 66 cm (26.0 in) | 23.8% |
| 78 cm (30.7 in) | 10.6% | 68 cm (26.8 in) | 24.9% |
| 80 cm (31.5 in) | 12.4% | 70 cm (27.6 in) | 25.9% |
| 82 cm (32.3 in) | 14.0% | 72 cm (28.3 in) | 26.9% |
| 84 cm (33.1 in) | 15.7% | 74 cm (29.1 in) | 27.9% |
| 86 cm (33.9 in) | 17.2% | 76 cm (29.9 in) | 28.9% |
| 88 cm (34.6 in) | 18.7% | 78 cm (30.7 in) | 29.9% |
| 90 cm (35.4 in) | 20.1% | 80 cm (31.5 in) | 30.9% |
| 92 cm (36.2 in) | 21.5% | 82 cm (32.3 in) | 31.9% |
| 94 cm (37.0 in) | 22.9% | 84 cm (33.1 in) | 32.9% |
| 96 cm (37.8 in) | 24.2% | 86 cm (33.9 in) | 33.8% |
| 98 cm (38.6 in) | 25.5% | 88 cm (34.6 in) | 34.8% |
| 100 cm (39.4 in) | 26.7% | 90 cm (35.4 in) | 35.7% |
| 102 cm (40.2 in) | 28.0% | 92 cm (36.2 in) | 36.6% |
| 104 cm (40.9 in) | 29.1% | 94 cm (37.0 in) | 37.6% |
| 106 cm (41.7 in) | 30.3% | 96 cm (37.8 in) | 38.5% |
| 108 cm (42.5 in) | 31.4% | 98 cm (38.6 in) | 39.4% |
| 110 cm (43.3 in) | 32.5% | 100 cm (39.4 in) | 40.3% |
| 112 cm (44.1 in) | 33.6% | 102 cm (40.2 in) | 41.2% |
| 114 cm (44.9 in) | 34.6% | 104 cm (40.9 in) | 42.0% |
| 116 cm (45.7 in) | 35.6% | 106 cm (41.7 in) | 42.9% |
| 118 cm (46.5 in) | 36.6% | 108 cm (42.5 in) | 43.8% |
Tips and pitfalls
- Measure the right spot. Men measure the waist at the navel; women at the narrowest point. Measure the neck just below the Adam's apple, and the hips at the widest point.
- Keep the tape level and relaxed. Do not suck in or pull the tape tight, and measure first thing in the morning for consistent readings.
- Track the trend. Any single estimate can be a few points out, but the same method repeated monthly shows clearly whether you are losing fat.
- Very muscular necks skew it. Large neck muscles lower the estimate, so strength athletes may read leaner than they are.
FAQ
What is a healthy body fat percentage?
For men, 14 to 24% is typical of fit to average adults, and for women 21 to 31%. Below about 6% for men or 14% for women is essential fat only, hard to sustain, and above 25% for men or 32% for women is classed as obese by the American Council on Exercise.
How accurate is the US Navy body fat method?
Studies comparing it with DEXA scans find it is usually within 3 to 4 percentage points for most adults. It tends to be less accurate for very lean, very muscular or very heavy people, but it is consistent, so it works well for tracking changes over time.
Why do women have higher body fat than men?
Women carry more essential fat in the breasts, hips and around the reproductive organs, which supports hormones and pregnancy. That is why the healthy ranges for women sit roughly 7 to 8 percentage points higher than for men at every fitness level.
Is body fat percentage better than BMI?
For an individual, usually yes. BMI uses only height and weight, so it labels muscular people overweight and can miss excess fat in people of normal weight. Body fat percentage measures composition directly, though BMI remains useful for large population studies.
How do I lower my body fat percentage?
Eat in a modest calorie deficit of around 300 to 500 kcal a day, keep protein high and strength train two to four times a week to hold on to muscle. Losing about 0.5 to 1% of body weight a week keeps the loss mostly fat rather than muscle.
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