Conversion factors fps/SI

Below are instructions for converting factors of the most important units of fps* to the SI-System

*fps - system: foot pound second-system

Unit	fps	SI (MKS)
Length	1 ft = 1/3 yd = 12 in	1ft = 0,3048 m; 1 mile = 1609,34 m
Area	1 ft² = 144 in²	1ft² = 0,092903 m²
Volume	1 ft³ = 1728 in³ = 6,22882 gal (UK) 1 gal (US) = 0,83268 gal (UK)	1ft³ = 0,0283169 m³ 1 bu = 35,2393 l; 1 bbt (US) = 115,627 l
Speed	1 ft/s 1 knot = 1,150785 mile/h =1,6877 ft/s	1ft/s = 0,3048 m/s
Acceleration	1 ft/s²	1ft/s = 0,3048 m/s²
Mass	1 lb = cwt/112; 1 sh tn = 2000 lb 1 slug = 32,174 lb; 1 in tn = 2240 lb	1lb = 0,453592 kg 1 slug = 14,5939 kg
Force	1 lbf 1 pdl = 0,031061 lbf	1 lbf = 4,44822 N 1 pdl = 0,138255 N
Work	1 ft lb = 0323832 calIT 1 btu = 252 calIT = 778,21 ft lb	1 ft lb = 1,35582 J 1 btu = 1,05506 kJ
Pressure	1 lb/ft² = 6,9444 x 10-3 lb/in² 1 lb/in² = 0,068046 atm 1 atm = 29,92 in Hg = 33,90 ft water	1 lb/ft² = 47,88 N/m² 1 lb/in² = 6894,76 N/m² 1 atm = 1,01325 bar
Density	1 lb/ft³ = 5,78704 x 10-4 lb/in³ 1 lb/gal = 6,22882 lb/ft³	1 lb/ft³ = 16,0185 kg/m³ 1 lb/gal = 99,7633 kg/m³
Temperature	32 °F = 0°C; 212 deg F = 100°C	1 °F = 0,5556 °C
Power	1 ft lb/s = 1,8182 x 10-3 hp = 1,28505 x 10-3 btu/s	1ft lb/s = 1,35582 W

Abbreviations and names of English units

atm	atmosphere
bbl	barrel
btu	British thermal unit
bu	bushel
cwt	hundredweight
cal	calorie
°F	degree Fahrenheit
ft	foot
gal	gallon
hp	horsepower
in	inch
lb	pound
lbf	pound force
ln tn	long ton
pdl	poundel
sh tn	short ton
yd	yard
UK	United Kingdom
US	United States of America
in/s	inch per second
in²	square inch
in³	cubic inch

Published by kind permission of Springer-Verlag, Heidelberg from: Dubbel, Taschenbuch für den Maschinenbau (Mechanical Engineering Paperbock), 17th edition (1990)

Note:
The belt tensile force related to belt width is converted as follows: 1 piw = 0,175 N/mm