Predicting Body Density and Percent Body Fat of Adults from Skinfold Thickness Using the Equations of Durnin and Womersley

Skinfold measurements:

(1) Measurements were usually taken on the right side with the patient in a relaxed condition.

(2) Sites measured: biceps, triceps, subscapular region, supra-iliac region

(3) The skinfold thickness is taken with a caliper tension of 9.8 * 10^4 newtons per square meter.

(4) Measurements <= 5 mm were taken to the nearest 0.5 mm; measurements > 5 mm were taken to the nearest mm.

(5) The authors found that subtracting 1.8 mm from each skinfold to take into account two layers of skin thickness during skinfold measurements did not improve results (page 80-81).

 

sum of 4 skinfolds =

= (thickness of biceps skinfold in mm) + (thickness of triceps skinfold in mm) + (thickness of subscapular skinfold in mm) + (thickness of supra-iliac skinfold in mm)

 

body density  in 1000 kg per cubic meter =

= c – (m * (LOG10 (total skinfolds in mm)))

 

where:

• 1 g per cc = 1000 kg per cubic meter

• Equations for the various combinations of skinfold thicknesses are given in Table 5, page 87.

• The standard errors for the equations are given in Table 4, page 82.

 

Male
Age in Years	c	m
17-19	1.1620	0.0630
20-29	1.1631	0.0632
30-39	1.1422	0.0544
40-49	1.1620	0.0700
50-72	1.1715	0.0779

from Table 5, page 86

 

Female
Age in Years	c	m
16-19	1.1549	0.0678
20-29	1.1599	0.0717
30-39	1.1423	0.0632
40-49	1.1333	0.0612
50-68	1.1339	0.0645

from Table 5, page 87

 

Siri Equation

 

percent body fat (from 0 to 100) =

= (((4.95 / (body density in grams per cubic cm)) - 4.5) * 100

 

Percent Body Fat

 

	Male with Age in Years
Total Sum Skinfolds mm	17-29	30 – 39	40 – 49	50 - 72
15	4.8
20	8.1	12.2	12.2	12.6
25	10.5	14.2	15.0	15.6
30	12.9	16.2	17.7	18.6
35	14.7	17.7	19.6	20.8
40	16.4	19.2	21.4	22.9
45	17.7	20.4	23.0	24.7
50	19.0	21.5	24.6	26.5
55	20.1	22.5	25.9	27.9
60	21.2	23.5	27.1	29.2
65	22.2	24.3	28.2	30.4
70	23.1	25.1	29.3	31.6
75	24.0	25.9	30.3	32.7
80	24.8	26.6	31.2	33.8
85	25.5	27.2	32.1	34.8
90	26.2	27.8	33.0	35.8
95	26.9	28.4	33.7	36.6
100	27.6	29.0	34.4	37.4
105	28.2	29.6	35.1	38.2
110	28.8	30.1	35.8	39.0
115	29.4	30.6	36.4	39.7
120	30.0	31.1	37.0	40.4
125	30.5	31.5	37.6	41.1
130	31.0	31.9	38.2	41.8
135	31.5	32.3	38.7	42.4
140	32.0	32.7	39.2	43.0
145	32.5	33.1	39.7	43.6
150	32.9	33.5	40.2	44.1
155	33.3	33.9	40.7	44.6
160	33.7	34.3	41.2	45.1
165	34.1	34.6	41.6	45.6
170	34.5	34.8	42.0	46.1
175	34.9
180	35.3
185	35.6
190	35.9
195
200
205
210

from Table 9, page 95

 

	Female with Age in Years
Skinfold mm	16-29	30 – 39	40 – 49	50 - 68
15	10.5
20	14.1	17.0	19.8	21.4
25	16.8	19.4	22.2	24.0
30	19.5	21.8	24.5	26.6
35	21.5	23.7	26.4	28.5
40	23.4	25.5	28.2	30.3
45	25.0	26.9	29.6	31.9
50	26.5	28.2	31.0	33.4
55	27.8	29.4	32.1	34.6
60	29.1	30.6	33.2	35.7
65	30.2	31.6	34.1	36.7
70	31.2	32.5	35.0	37.7
75	32.2	33.4	35.9	38.7
80	33.1	34.3	36.7	39.6
85	34.0	35.1	37.5	40.4
90	34.8	35.8	38.3	41.2
95	35.6	36.5	39.0	41.9
100	36.4	37.2	39.7	42.6
105	37.1	37.9	40.4	43.3
110	37.8	38.6	41.0	43.9
115	38.4	39.1	41.5	44.5
120	39.0	39.6	42.0	45.1
125	39.6	40.1	42.5	45.7
130	40.2	40.6	43.0	46.2
135	40.8	41.1	43.5	46.7
140	41.3	41.6	44.0	47.2
145	41.8	42.1	44.5	47.7
150	42.3	42.6	45.0	48.2
155	42.8	43.1	45.4	48.7
160	43.3	43.6	45.8	49.2
165	43.7	44.0	46.2	49.6
170	44.1	44.4	46.6	50.0
175		44.8	47.0	50.4
180		45.2	47.4	50.8
185		45.6	47.8	51.2
190		45.9	48.2	51.6
195		46.2	48.5	52.0
200		46.5	48.8	52.4
205			49.1	52.7
210			49.4	53.0

from Table 9, page 95

 

Approximating Equations from JMP

 

Males with Sum of Skinfolds <= 90 mm

 

percent fat for males 17-29 years old with skinfold 15-90 mm =

= (0.000041 * ((total skinfold)^3)) – (0.00932 * ((total skinfold)^2)) + (0.866067 * (total skinfold)) – 6.00107

 

percent fat for males 30-39 years old with skinfold 20-90 mm =

= (0.0000241 * ((total skinfold)^3)) – (0.006048 * ((total skinfold)^2)) + (0.6400706 * (total skinfold)) + 1.6609664

 

percent fat for males 40-49 years old with skinfold 20-90 mm =

= (0.0000365 * ((total skinfold)^3)) – (0.008677 * ((total skinfold)^2)) + (0.8749747 * (total skinfold)) – 2.002712

 

percent fat for males 50-72 years old with skinfold 20-90 mm =

= (0.0000429 * ((total skinfold)^3)) – (0.010065 * ((total skinfold)^2)) + (0.99782 * (total skinfold)) – 3.637384

 

Males with Sum of Skinfolds >= 90 mm

 

percent fat for males 17-29 years old with skinfold 90-190 mm =

= (0.0000015 * ((total skinfold)^3)) – (0.001 * ((total skinfold)^2)) + (0.285045 * (total skinfold)) + 7.5579898

 

percent fat for males 30-39 years old with skinfold 90-170 mm =

= (0.0000026 * ((total skinfold)^3)) – (0.0014* ((total skinfold)^2)) + (0.3141237 * (total skinfold)) + 8.9496

 

percent fat for males 40-49 years old with skinfold 90-170 mm =

= (0.0000014 * ((total skinfold)^3)) – (0.000961 * ((total skinfold)^2)) + (0.2892191 * (total skinfold)) + 13.707379

 

percent fat for males 50-72 years old with skinfold 90-170 mm =

= (0.0000002 * ((total skinfold)^3)) – (0.000594* ((total skinfold)^2)) + (0.274175 * (total skinfold)) + 15.78274

 

Females with Sum of Skinfolds <= 90 mm

 

percent fat for females 16-29 years old with skinfold 15-90 mm =

= (0.0000426 * ((total skinfold)^3)) – (0.009878 * ((total skinfold)^2)) + (0.94845 * (total skinfold)) – 1.432143

 

percent fat for females 30-39 years old with skinfold 20-90 mm =

= (0.0000323 * ((total skinfold)^3)) – (0.00782 * ((total skinfold)^2)) + (0.797252 * (total skinfold)) + 3.9435567

 

percent fat for females 40-49 years old with skinfold 20-90 mm =

= (0.0000351 * ((total skinfold)^3)) – (0.008319 * ((total skinfold)^2)) + (0.8182132 * (total skinfold)) + 6.4602618

 

percent fat for females 50-68 years old with skinfold 20-90 mm =

= (0.0000368 * ((total skinfold)^3)) – (0.008741 * ((total skinfold)^2)) + (0.8658072 * (total skinfold)) + 7.3191546

 

Females with Sum of Skinfolds >= 90 mm

 

percent fat for females 16-29 years old with skinfold 90-170 mm =

= (0.0000021 * ((total skinfold)^3)) – (0.001291 * ((total skinfold)^2)) + (0.3404369 * (total skinfold)) +13.092466

 

percent fat for females 30-39 years old with skinfold 90-200 mm =

= (0.0000005 * ((total skinfold)^3)) – (0.000519 * ((total skinfold)^2)) + (0.2163384 * (total skinfold)) + 20.274699

 

percent fat for females 40-49 years old with skinfold 90-200 mm =

= (0.0000009 * ((total skinfold)^3)) – (0.000711 * ((total skinfold)^2)) + (0.2388038 * (total skinfold)) + 21.965364

 

percent fat for females 50-68 years old with skinfold 90-210 mm =

= (0.0000011 * ((total skinfold)^3)) – (0.000801 * ((total skinfold)^2)) + (0.2600804 * (total skinfold)) + 23.492094