141
Metric System Conversion Factors
Bert McCarty
Metric Prefix Definitions (basic metric unit = 1)
tera
=
1012
deci
=
10-1
giga
=
109
centi
=
10-2
mega
=
106
milli
=
10-3
kilo
=
103
micro
=
10-6
hecto
=
102
nano
=
10-9
deca
=
101
pico
=
10-12
Metric Prefix Example (weight)
Metric Prefix Example (volume)
1 kg
=
103 g
=
106 mg
=
109 μg
=
1012 ng
1L
=
103 mL
=
106 μL
1g
=
10-3 kg
=
103 mg
=
106 μg
=
109 ng
1 mL
=
10-3 L
=
10-6 μL
1 mg
=
10-6 kg
=
10-3 g
=
103 μg
=
106 ng
1 μL
=
10-6 L
=
10-3 mL
1 μg
=
10-9 kg
=
10-6 g
=
10-3 mg
=
103 ng
1 ng
=
1012 kg
=
10-9 g
=
10-6 mg
=
10-3 μg
Area Equivalents
2
=
4840 yd
=
0.4047 hectares (ha)
=
160 rods
2
=
100 are
=
2.471 acres
=
107,639 ft
1 acre
=
43,560 ft
1 ha
=
10,000 m
2
=
9 ft
1 ft
2
=
144 in
1 ft
3
=
1728 in
=
102.8 m
1 yd
1 acre-inch
2
2
2
=
0.836 m
=
929.03 cm
=
0.09290 m
3
=
0.037 yd
3
=
0.02832 m
3
=
27,154 gal
=
3630 ft
2
2
4047 m
3
=
27 ft
2
=
10,000 cm
1 yd
2
2
=
0.0016 mi
=
0.765 m
2
2
1m
3
2
=
3
3
2
3
=
28,320 cm
3
Liquid Equivalents
1 gal
=
1 qt
4 qt
=
3
8 pt
=
16 cups
=
231 in
=
256 tbsp
=
0.134 ft
=
0.9463 L
=
2 pt
=
4 cups
3
=
128 fl oz
=
8.337 lb
=
3.785 L
=
3785 ml
=
32 fl oz
=
64 tbsp
1 barrel
=
3
57.75 in
2
=
946.4 ml
=
1,000 cm
=
42 gal
3
1L
=
2.113 pt
=
1000 ml
=
1.057 qt
=
33.8 fl oz
=
0.26 gal
=
0.0001m
1 pt
=
16 fl oz
=
2 cups
=
473.2 ml
=
32 tbsp
=
0.125 gal
=
0.5 qt
1 cup
=
8 fl oz
=
0.5 pt
=
16 tbsp
=
236.6 ml
1 tbsp
=
14.8 ml
=
3 tsp
=
0.5 fl oz
1 floz
=
29.57 ml
=
2 tbsp
=
6 tsp
=
0.0313 qt
1 tsp
=
4.93 ml
=
0.1667 floz
=
80 drops
=
0.034 floz
=
0.002 pts
3
=
1 ft of water
7.5 gal
=
62.4 lb
=
28.3 L
1 ml
=
3
1 cm
Pressure Equivalents
1 mmHg
=
1Pa
=
133.32 Pa
-3
10 kPa
=
10 mPa
1 PSI
=
6.9 kPa
=
2.31 ft head
3
=
0.133 kPa
Temperature Equivalents
=
133,333 mPa
-6
6
1mPa
=
10 kPa
=
10 Pa
=
10 bar
1 atm
=
760 mmHg
=
29.92 in Hg
=
1.013 x 10 Pa
1kPa
=
0.001mPa
=
10 cm H2O
=
10 mbar
=
5
0.01 bar
ºC
=
(°F-32)
x
5/9
ºF
=
(°Cx9/5)
+
32
=
100 N cm
=
14.69 psi
=
33.89 ft water
=
0.0099 atm
=
0.145 psi
=
10.2 kg cm-
=
1.013 bar
=
-1
1J kg
2
-2
142
Length Equivalents
km
=
0.621 statute mile
=
1,000 m
=
100,000 cm
=
3,281 ft
=
39,370 in
m
=
3.28 ft
=
39.4 in
=
100 cm
=
1.094 yd
=
1,000 mm
cm
=
0.3937 in
=
0.01 m
=
0.03281 ft
in
=
2.54 cm
=
25.4 mm
=
0.0254 m
=
0.08333 ft
ft
=
0.3048 m
=
30.48 cm
=
12 in
yd
=
0.9144 m
=
3 ft
=
91.44 cm
statute mile
=
1,760 yd
=
5,280 ft
=
1.61 km
=
1609 m
Mixture Ratios
-1
1 mg g
1 floz 100 gal
1 pt 100 gal
-1
-1
Flow
-1
=
1000 ppm
=
1 fl oz gal
=
75 ppm
=
1 qt 100 gal
=
1 tsp gal
7490 ppm
-1
2 tbsp gal
-1
3
1 ft sec
-1
-1
=
1 gpm
=
1 ft min
3
-1
3
-1
=
0.06308 L sec
-1
=
7.481 gal min
=
0.134 ft min
=
448.83 gal hr
-1
-1
-1
=
448.83 gal min
Weight Equivalents
1 ton (US)
=
2,000 lb
=
0.907 metric
tons
=
907.2 kg
1 lb
=
16 oz
=
453.6 g
=
0.4536 kg
1g
=
1,000 mg
=
0.0353 oz
=
0.001 kg
1 kg
=
1,000 g
=
35.3 oz
=
2.205 lbs
ng
=
-9
10 g
=
1% (v/v)
=
1.28 fl oz
-1
gal
=
1 gal 100 gal
1 ppm
=
0.0001%
=
1 mg kg
=
0.379 g
-1
100 gal
=
8.34 x 10 lb
-1
gal
100 ppm
=
0.01%
=
100 mg L
1 ppb
=
1 µg kg
=
1 µg L
-1
1 metric ton
=
6
=
0.002205 lb
0.001 micrograms (µg)
-
1
-1
-6
10,000 ppm
=
1 mg L
=
0.013 fl oz 100 gal
-1
-1
=
10g L
=
1 µg g
-1
1,000 kg
=
2,205 lb
1 oz (wt)
=
28.35 g
=
0.0625 lb
1 mg
=
0.001 g
1 µg
=
10 g
=
0.001 mg
=
8.34 lb 100 gal
1 ng ml
-1
=
10
1.33 oz
-1
(wt) gal
-1
=
1μg ml
10 ppm
=
0.001%
=
10 mg L
=
0.1%
=
1,000 mg L
1 ppt
=
1 picogram g
=
1µl L
1 ng 1,000,000,000
-12
=
1g 100ml
1
-1
=
-6
=
=
-1
1,000 ppm
=
=
picogram
=
-1
-1
10 g
1 mg g
-1
-
g
-1
Water and Soil Calculations
1 mmhos cm
-1
=
1 dS m-1
1 mmol L-1
=
1mol m-3
1mmol 100g-1
=
cmol kg-1
=
1,000 μmhos cm
1 meq L-1
=
1 meq 100g-1
=
-1
=
0.1 S m-1
=
1mS cm-1
=
10 meq L-1
Electrical conductivity (mmhos cm-1 or dS m-1)
x 640
=
Total dissolved salts (mg L-1 or ppm)
Total dissolved salts (mg L-1 or ppm)
x 0.0016
=
Electrical conductivity (mmhos cm-1 or ds m-1)
1 calorie (cal)
Joule (J)
1 kcal
Energy
=
4.184 Joule (J)
=
1 kg m2 s-2
=
4.184 kJ
-1
-1
-1
-1
143
Decimal and Millimeter Length Equivalents
Fraction (inch)
1
15/16
7/8
13/16
¾
11/16
5/8
9/16
½
7/16
3/8
11/32
5/16
9/32
¼
15/64
7/32
13/64
1/5
3/16
23/128
11/64
1/6
21/128
5/32
1/7
19/128
9/64
⅛
7/64
1/10
3/32
5/64
1/16
3/64
1/32
1/64
Decimals (inch)
1.00
0.9375
0.875
0.8125
0.75
0.6875
0.625
0.5625
0.5
0.4375
0.3750
0.34375
0.3125
0.28125
0.25
0.234375
0.21875
0.203125
0.200
0.1875
0.1797
0.171875
0.167
0.1641
0.15625
0.143
0.1484
0.140625
0.1250
0.109375
0.100
0.09375
0.078125
0.0625
0.046875
0.03125
0.015625
Millimeters
25.4
23.812
22.225
20.638
19.05
17.462
15.875
14.288
12.70
11.112
9.525
8.731
7.938
7.144
6.350
5.953
5.556
5.159
5.08
4.762
4.564
4.366
4.242
4.168
3.969
3.633
3.769
3.572
3.175
2.778
2.540
2.381
1.984
1.588
1.191
0.794
0.397
144
Metric Conversion
To Convert
Multiply by
To Obtain
Acres (a)
0.4047
hectare (ha)
Acres
Acres
Acres
43,560
0.00405
4047
sq. feet (ft2)
sq. kilometer (km2)
sq. meter (m2)
Acres
Acre-feet
4840
325,851
sq. yards (yd2)
sq. feet (ft2)
Acre-feet
Acre-feet
43560
1233.5
cu. feet (ft3)
cu. meter (m3)
Acre-inch
Bar
102.8
14.5
m3
lb/in2
Bar
1019.7
g/cm3
Bar
Bar
Bar
Bar
29.53
75
0.001
100
inches Hg @ 0oC
cm Hg @ 0oC
J/kg
kPa
Bushels - dry
0.03524
m2
Bushels
Calorie (cal)
Centimeters (cm)
1.245
4.184
0.03281
ft3
Joules (J)
feet (ft)
cm
cm
0.3937
0.1094
inches (in)
yards (yd)
cm
cm
cm/sec = cm sec-1 = cm per sec
cm/sec
0.01
10
1.9685
0.0223694
meters (m)
millimeters (mm)
ft/min
miles per hour (MPH)
cm2 (square centimeters)
0.001076
ft2
0.1550
0.01
in2
sq. decimeter
0.0610237
0.0338
0.001057
in3
fl oz
qt3
cm3
cm3
Cup
Cup
Feet (ft)
ft
0.000264172
0.001
8
236.6
30.48
0.3048
gal
cu. decimeter
fl oz
cm3
cm
m
ft
ft2 (square feet)
ft2
ft2
ft2
305
929
0.0929
9.294 x 10-6
144
mm
cm2
m2
hectares (ha)
in2
cm2
cm2
cm3 (cubic centimeters)
cm3
cm3
145
Metric Conversion
To Convert
ft3 (cubic feet)
Multiply by
0.0283
To Obtain
m3
ft3
ft3
ft3
ft3
ft3/1,000 ft2
7.4805
1728
0.037
28.32
0.030463
gallons
cubic inches (in3)
cubic yards (yd3)
liters (L)
m3/100 m2
Feet per minute
Feet head of water
Foot candle
Gallons (gal)
Gal
0.01136
0.433
10.764
3.785
3785
mph
psi
lux
liters
ml
Gal
Gal
Gal
Gal
Gal per acre (gpa)
128
0.13368
231
3,785
9.354
ounces (liquid)
ft3
in3
cm3
L/ha
0.09354
2.938
4.0746
2.228 x 10-3
0.06309
L/100 m2
oz/1,000 ft2 (liquid)
L/100 m2
ft3/second
L/sec
Gal/min
Grams (g)
Gram
g/cm3
g/cm3
0.227125
0.002205
0.035274
0.036127
62.428
m3/hr
lb
oz
lb/in3
lb/ft3
g/ft2
g/ha
g/ha
g/kg
g/liter
g/liter
96
0.000893
0.014275
0.10
1000
10
lb/acre
lbs/acre
oz/acre
percent (%)
PPM
%
0.00834595
0.13351
0.00020481
0.20481
2.471
lb/gal
oz/gal
lb/ft2
lb/1,000 ft2
Acres
107,639
107.64
746
550
33,000
ft2
1,000 ft2
watts
ft-lbs/sec
ft-lbs/min
gpa
gpa
Gal/1,000 ft2
Gal/minute
Gal/min
g/liter
g/liter
g/m2
g/m2
Hectares (ha)
Ha
Ha
horsepower (electrical or mechanical)
hp
hp
146
Metric Conversion
To Convert
hp
Multiply by
1.014
To Obtain
metric horsepower
hp
Inches (in)
Inches
Inches
Inches of mercury
33,000
2.540
0.0254
25.40
3.4
ft lbs/min
cm
m
ml
kilopascals (kPa)
in/acre
in/ft
in2
in3
in3
6.28
0.083
6.4516
16.3871
0.55411
cm/ha
mm/mm
cm2
cm3
fl oz
in3
in3/hr
Joules per kilograms (J/kg)
kilo Pascal (kPa)
kPa
0.01732
0.00434
1
1
1
qt
gal/hr
kPa
J/kg
0.01 bar
kPa
Kilograms (kg)
kg/hectare
kg/ha
kg/100 m2
0.01
2.2046
0.892
0.02048
2.048
bar
lb
lb/acre
lb/1,000 ft2
lbs/1,000 ft2
kg/L
Kilometers (Km)
Kilometers
Kilometers
Kilometers
8.3454
100,000
3281
1000
0.6214
lb/gal
cm
ft
m
miles
Kilometers
Km/h
Km/h
Kilopascals (kPa)
kPa
kPa
1094
0.62137
54.6807
0.145
1
1
yd
mph
ft/min
lbs/in2 (psi)
0.01 bar
J/kg
Liters (L)
L
L
L
L
0.2642
33.814
2.113
1.057
0.035315
gallons
fl.oz.
pt
qt
ft3
3.2808
0.2454
1.9634
0.107
0.0025
ft3/1,000 ft2
gal/1,000 ft2
pt/1,000 ft2
gal/A
gal/1,000 ft2
L/m2
L/100 m2
L/100 m2
Liters/hectare
L/ha
147
Metric Conversion
To Convert
L/ha
Multiply by
0.314
To Obtain
oz/1,000 ft2
L/ha
L/min
Meters (m)
Meters
Meters
0.855
15.85
3.281
39.37
1.094
pt/A
gal/hr
ft
in
yd
Meters
Meters
Meters
Meters/sec
M2 (square meters)
100
0.001
1000
2.2369
10.764
cm
km
mm
mph
ft2
M2
M2
M3 (cubic meters)
M3
M3
1,550
1.196
35.3147
1.30795
1,000
in2
yd2
ft3
yd3
L
M3/ha
M3/ha
M3/ha
mil
mil
14.29
0.0122
0.328
0.001
0.0254
ft3/acre
yd /1,000 ft2
ft3/1,000 ft2
in
mm
Miles (nautical)
Miles (nautical)
Miles (statute)
Miles
Miles
1.1508
6,076
160,900
5280
1.609
miles (statute)
ft
cm
ft
km
1760
1.467
88
1.61
0.447
1
yards
ft/sec
ft/mine
km/hr
m/sec
parts per million (ppm)
1
Eq. wt. x 10
1
1,000
0.0338
millimoles per liter (mmol/L)
parts per million (ppm)
decisiemens per meter (dS/m)
micromhos per centimeter (μmhos/cm)
oz (fluid)
0.0002642
3.14
0.12793
0.0128
0.03937
gal
oz/1,000 ft2
oz/gal
fl oz/1,000 gal
in
Miles
Miles per hour (mph)
mph
mph
mph
mg/kg
Milliequivalents per liter (meq/L)
Milliequivalents per 100 g (meq/100g)
Millimhos per centimeter (mmhos/cm)
mmhos/cm
Milliliters (ml)
ml
ml/m2
ml/l
ml/10,000 L
Millimeters (mm)
3
148
Metric Conversion
To Convert
1 mm Hg @ 0 C
Multiply by
0.13332
To Obtain
kPa
133333.3
0.02957
29.573
0.03125
7.81
mPa
L
ml
qt.
ml/L
Ounces (fluid)/acre
Ounces (fluid)/acre
Ounces (fluid)/1,000 ft2
oz (weight)
oz (weight)
0.0731
73.1
3.18
28.35
0.0625
L/ha
ml/ha
L/ha
g
lb
oz (weight)/acre
oz (weight)/acre
oz (weight)/1,000 ft2
oz (weight)/ft2
oz (weight)/gal
0.07
70
3.05
305.15
7.5
kg/ha
g/ha
kg/ha
g/m2
g/L
oz (weight)/1,000 ft2
Percent (%)
Pint (liquid) (pt)
pt/A
pt/A
0.305
10
0.473
1.1692
0.3673
g/m2
g/kg
liter
L/ha
oz/1,000 ft2
pt/1,000 ft2
Parts per million (ppm)
PPM
PPM
PPM
0.50932
2.719
2.0
2.25
0.001
L/100 m2
lb ai/acre foot of water
lbs/acre slice 7-in. deep
kg/ha slice 7-in. deep
g/L
PPM
PPM
PPM
PPM
PPM
Pounds (lb)
8.34
1
0.013
0.3295
8.2897
0.4536
lb/million gal
mg/kg
oz/100 gal of water
gal/acre-foot of water
lbs/million gal of water
kilograms (kg)
lb
lb/acre
lb /acre
lb /acre
lb / acre
453.6
1,120
1.12
1.0413
0.02296
g
g/ha
kg/ha
g/100 ft2
lb/1,000 ft2
0.112
0.3682
0.0003682
4883
16.23
g/m2
g/m3
kg/m3
g/m2
kg/m3
1 mm Hg
Ounces (fluid) (oz)
Ounces (fluid)
Ounces (fluid)
Oz (fluid)/gal
lb /acre
lb /acre-foot
lb /acre-foot
lb / ft2
lb /ft3
149
Metric Conversion
To Convert
lb /1,000 ft2
Multiply by
4.88
To Obtain
g/m2
lb /1,000 ft2
lb /1,000 ft2
lb /1,000 ft2
lb /1,000 ft2
lb /1,000 ft2
48.83
43.5597
488
0.4883
0.91
kg/ha
lb/A
g/100 m2
kg/100 m2
lbs/100 yd2
lb /1,000 ft2
lb /yd3
lb /yd3
lb /yd3
lb /gallon
1.1
0.0005937
594
0.5932
0.12
lbs/1,000 ft2
g/cm3
g/m3
kg/m3
kg/liter
lb /1,000 gal
pounds per square inch (PSI)
PSI
PSI
PSI
0.12
6.89
0.06895
0.068046
2.31
g/1,000 L
kilopascals (kPa)
bar
atmosphere (atm)
feet head of water
Quarts (qt)
Quarts
Qt/A
Qt/A
Qt/100 gal
0.9463
946
2.3385
0.7346
2.5
L
ml
L/ha
oz/1,000 ft2
ml/L
Temperature, C 1 . 8
Temperature, F- 32
Ton (2,000 lbs)
Ton (2,000 lbs)/acre
Ton (2,000 lbs)
1.8
0.5555
907
2240
0.907
temperature, F
temperature, C
kg
kg/ha
ton (metric)
Ton (2,000 lbs)/acre
Ton (metric)
Ton (metric)
Ton (metric)
Yards (yd)
Yards
2.241
2,205
1,000
1.102
91.44
0.9144
ton (metric)/ha
lb
kg
ton (2,000 lb)
cm
m
Yards
square yards (yd2)
yd2
yd2
cubic yards (yd3)
914.4
0.836
9
1,296
27
mm
m2
ft2
in2
ft3
yd3
yd3
yd3
yd3/1,000 ft2
P2O5
46,656
0.7645
765
0.825
0.437
in3
m3
L
m3/100 m2
P
150
Metric Conversion
To Convert
K2O
Multiply by
0.830
To Obtain
K
0.715
0.602
400
Ca
Mg
+2
lb Ca per acre furrow slice
meq K+/100 g soil
780
lb K+ per acre furrow slice
meq Na+/100 g soil
460
lb Na+ per acre furrow slice
meq Mg+2/100 g soil
109
lb Mg+2 per acre furrow slice
meq Fe+3/100 g soil
372
lb Fe+3 per acre furrow slice
meq Zn+2/100 g soil
654
lb Zn+2 per acre furrow slice
meq H+/100 g soil
20
lb H+ per acre furrow slice
meq Al+3/100 g soil
180
lb Al+3 per acre furrow slice
meq Ca+2/100 g soil
9.2
lb Ca+2 per 1,000 ft2 furrow slice
meq K+/100 g soil
18
lb K+ per 1,000 ft2 furrow slice
meq Na+/100 g soil
10.6
lb Na+ per 1,000 ft2 furrow slice
meq Mg+2/100 g soil
2.5
lb Mg+2 per 1,000 ft2 furrow slice
meq Fe+3/100 g soil
8.5
lb Fe+3 per 1,000 ft2 furrow slice
meq Zn+2/100 g soil
15
lb Zn+2 per 1,000 ft2 furrow slice
meq H+/100 g soil
0.46
lb H+ per 1,000 ft2 furrow slice
meq Al+3/100 g soil
4.1
lbs Al+3 per 1,000 ft2 furrow slice
CaO
MgO
meq Ca+2/100 g soil