US Units as used by structural and foundation engineers are converted to SI Units

Unit Conversion Factors

 

From  English	To  SI	Multiply by	CATEGORY	From  SI	To  English	Multiply by
ft	m	0.3048	Length	m	ft	3.2808
inch	mm	25.40		mm	inch	0.039
ft2	m2	0.0929	Area	m2	ft2	10.764
inch2	mm2	645.2		mm2	inch2	0.0015
ft3	m3	0.028	Volume	m3	ft3	35.714
inch3	mm3	16387		mm3	inch3	61x10-6
ft4	m4	0.0086	2nd Moment	m4	ft4	115856
inch4	mm4	416231	of Area	mm4	inch4	2x10-6
lbm	kg	0.4536	Mass	kg	lbm	2.2046
lbm/ft3	kg/m3	16.02	Mass Density	kg/m3	lbm/ft3	0.062
lb	N	4.448	Force	N	lb	0.2248
kip	kN	4.448		kN	kip	0.2248
lbs/ft	N/m	14.59	Force/Unit	N/m	lbs/ft	0.0685
kips/ft	kN/m	14.59	Length	kN/m	kips/ft	0.0685
lbs/in2	kPa	6.895	Force/Unit	kPa	lbs/in2	0.145
kips/in2	MPa	6.895	Area (Stress,	MPa	kips/in2	0.145
lbs/ft2	Pa	47.88	Pressure,	Pa	lbs/ft2	0.021
kips/ft2	kPa	47.88	Elastic Mod.)	kPa	kips/ft2	0.021
lbs/ft3	N/m3	157.1	Force/Unit	N/m3	lbs/ft3	0.0064
kips/ft3	kN/m3	157.1	Volume	kN/m3	kips/ft3	0.0064
lb-inch	N-mm	112.98	Moment	N-mm	lb-inch	0.0089
kip-inch	kN-mm	112.98	or	kN-mm	kip-in	0.0089
lb-ft	N-m	1.356	Energy	N-m	lb-ft	0.7375
kip-ft	kN-m	1.356		kN-m	kip/ft	0.7375
ft-lb	Joule	1.356		Joule	ft-lb	0.7375
ft-kip	kJoule	1.356		kJoule	ft-kip	0.7375
s/ft	s/m	3.2808	Damping	s/m	s/ft	0.3048
blows/ft	blows/m	3.2808		blows/m	blows/ft	0.3048