# Planning for Transportation Systems Management and Operations Within Corridors: A Desk Reference

## SI* (Modern Metric) Conversion

APPROXIMATE CONVERSIONS TO SI UNITS
SYMBOL WHEN YOU KNOW MULTIPLY BY TO FIND SYMBOL

LENGTH

in

inches 25.4 millimeters mm

ft

feet 0.305 meters m

yd

yards 0.914 meters m

mi

miles 1.61 kilometers km

AREA

in2

square inches 645.2 square millimeters mm2

ft2

square feet 0.093 square meters m2

yd2

square yard 0.836 square meters m2

ac

acres 0.405 hectares ha

mi2

square miles 2.59 square kilometers km2

VOLUME

fl oz

fluid ounces 29.57 milliliters mL

gal

gallons 3.785 liters L

ft3

cubic feet 0.028 cubic meters m3

yd3

cubic yards 0.765 cubic meters m3

NOTE: volumes greater than 1000 L shall be shown in m3

MASS

oz

ounces 28.35 grams g

lb

pounds 0.454 kilograms kg

T

short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t")
TEMPERATURE (exact degrees)

oF

Fahrenheit

5 (F-32)/9
or (F-32)/1.8

Celsius oC

ILLUMINATION

fc

foot-candles 10.76 lux lx

fl

foot-Lamberts 3.426 candela/m2 cd/m2

FORCE and PRESSURE or STRESS

lbf

poundforce 4.45   newtons N

lbf/in2

poundforce per square inch 6.89 kilopascals kPa

APPROXIMATE CONVERSIONS FROM SI UNITS
SYMBOL WHEN YOU KNOW MULTIPLY BY TO FIND SYMBOL

LENGTH

mm

millimeters

0.039

inches in

m

meters

3.28

feet ft

m

meters

1.09

yards yd

km

kilometers

0.621

miles mi

AREA

mm2

square millimeters

0.0016

square inches in2

m2

square meters

10.764

square feet ft2

m2

square meters

1.195

square yards yd2

ha

hectares

2.47

acres ac

km2

square kilometers

0.386

square miles mi2

VOLUME

mL

milliliters

0.034

fluid ounces fl oz

L

liters

0.264

gallons gal

m3

cubic meters

35.314

cubic feet ft3

m3

cubic meters

1.307

cubic yards yd3

MASS

g

grams

0.035

ounces oz

kg

kilograms

2.202

pounds lb

Mg (or "t")

megagrams (or "metric ton")

1.103

short tons (2000 lb) T

TEMPERATURE (exact degrees)

oC

Celsius 1.8C+32 Fahrenheit oF

ILLUMINATION

lx

lux

0.0929

foot-candles fc

cd/m2

candela/m2

0.2919

foot-Lamberts fl

FORCE and PRESSURE or STRESS

N

newtons 0.225 poundforce lbf

kPa

kilopascals

0.145

poundforce per square inch lbf/in2
 United States Department of Transportation - Federal Highway Administration