Metric Conversions

 

Fractional
Value
Decimal
Equivalent
Millimeters Fractional
Value
Decimal
Equivalent
Millimeters
1/64″ .015625 0.3968 33/64″ .515625 13.0966
1/32″ .03125 0.7937 17/32″ .53125 13.4934
3/64″ .046875 1.1906 35/64″ .546875 13.8903
1/16″ .0625 1.5875 9/16″ .5625 14.2872
5/64″ .078125 1.9843 37/64″ .578125 14.6841
3/32″ .09375 2.3812 19/32″ .59375 15.0809
7/64″ .109375 2.7780 39/64″ .609375 15.4778
1/8″ .1250 3.1749 5/8″ .6250 15.8747
9/64″ .140625 3.5718 41/64″ .640625 16.2715
5/32″ .15626 3.9686 21/32″ .65625 16.6684
11/64″ .171875 4.3655 43/64″ .671875 17.0653
3/16″ .1875 4.7624 11/16″ .6875 17.4621
13/64″ .203125 5.1592 45/64″ .703125 17.8590
7/32″ .21875 5.5561 23/32″ .71875 18.2559
15/64″ .234375 5.9530 47/64″ .734375 18.6527
1/4″ .2500 6.3498 3/4″ .7500 19.0496
17/64″ .265625 6.7467 49/64″ .765625 19.4465
9/32″ .28125 7.1436 25/32″ .78125 19.8433
19/64″ .296875 7.5404 51/64″ .796875 20.2402
5/16″ .3125 7.9373 13/16″ .8125 20.6371
21/64″ .328125 8.3342 53/64″ .828125 21.0339
11/32″ .34375 8.7310 27/32″ .84375 21.4308
23/64″ .359375 9.1279 55/64″ .859375 21.8277
3/8″ .3750 9.5248 7/8″ .8750 22.2245
25/64″ .390625 9.9216 57/64″ .890625 22.6214
13/32″ .40625 10.3185 29/32″ .90625 23.0183
27/64″ .421875 10.7154 59/64″ .921875 23.4151
7/16″ .4375 11.1122 15/16″ .9375 23.8120
29/64″ .453125 11.5091 61/64″ .953125 24.2089
15/32″ .46875 11.9060 31/32″ .96875 24.6057
31/64″ .484375 12.3029 63/64″ .984375 25.0026
1/2″ .5000 12.6997 1″ 1.0000 25.3995

 

  • 32 points of a compass = 360 degrees
  • 1 point of a compass = 11.25 degrees
  • To convert degrees C. to degrees F., multiply by 9, divide by 5 and add 32
  • To convert degrees F. to degrees C., deduct 32, multiply by 5 and divide by 9
  • 1 inch = 2.54 centimeter
  • 1 foot (U.S.) = .3048 meters = 1 British foot
  • 1 kilometer = 3,280.8399 feet = .5399568 nm
  • Statute mile = 5,280 ft = 1.609 km = .869 nm
  • Nautical mile = 1.15 stat miles = 1,852 m = 6,076.12 ft = about 2,000 yds (1 minute of latitude)
  • Length of 1 minute of latitude at equator = approximately 6,046 ft
  • Length of 1 minute of latitude at poles = approximately 6,108 ft
  • Knot = 1 nm/hr = 1.15 mph = 1.852 km/hr
  • Fathom = 6 ft = 1.829
  • Cable = 720 feet = 120 fathom
  • Cable (British) = .1 n
  • 7.5 cables = 1 statute mil
  • 8.44 cables = 1 nm
  • Charts – nautical miles per inch = reciprocal of natural scale/72,913.39
  • Charts – statute miles per inch = reciprocal of natural scale/63,360
  • Charts – inches per nm = 72,913.39 x natural scale
  • Charts – inches per sm = 63,360 x natural scale
  • Charts – natural scale = 1:72,913.39 x nm/inch
  • Charts – natural scale = 1:63,360 x sm/inch
  • Std. atmospheric pressure at sea level = 29.92126 inches of mercury
  • millibar = .02952998 inches of mercury
  • millimeter of mercury = 1.3332237 millibars
  • register ton = 100 cubic feet
  • measurement ton = 40 cubic feet = 1 freight ton
  • 1 barrel (42 gals) of diesel fuel = 315 pounds
  • 1 gallon of engine motor oil = 7.3 pounds
  • 1 cubic foot = 7.481 gals of water
  • cubic foot of seawater = 64 lbs
  • cubic foot of freshwater = 62.428 lbs @39.2 degrees F. (temp. of max. density)
  • 1 cubic foot of normal storage ice = 62 lbs
  • Speed of sound is approximately 1,117 feet per second
  • Approximate distance (nm) of a flash of light to resulting sound = elapsed time divided by 5.5
  • 1 displacement ton = 35 cubic feet of seawater = 1 long ton
  • 1 ton of freshwater=35.84 cubic feet

(Note: some values above are based upon relationships enumerated in Bowditch’s American Practical Navigator, Vol. I, 1984)

Temperature Conversions

  • Fahrenheit = 9 x Celsius ÷ 5 + 32
  • Celsius = Fahrenheit – 32 x 5 ÷ 9

Measurement Conversions and Equivalents

If you know the length in the English system… multiply by… to convert to … If you know the length in the Metric system… multiply by… to convert to …
inches 25.0 millimeters millemeters 0.04 inches
inches 2.5 centimeters centimeters 0.4 inches
feet 30.0 centimeters centimeters 0.033 feet
feet 0.3 meters meters 3.3 feet
yards 90.0 centimeters centimeters 0.01 yards
yards 0.9 meters meters 1.1 yards
miles 1.6 kilometer kilometers 0.62 miles

Weight Conversions and Equivalents

If you know the weight in the English system… multiply by… to convert to … If you know the weight in the Metric system… multiply by… to convert to …
ounces 28.0 grams grams 0.035 ounces
ounces 0.028 kilograms kilograms 35.0 ounces
pounds 454.0 grams grams 0.002 pounds
pounds 0.45 kilograms kilograms 2.2 pounds

Metric Length Equivalents

Metric English
millimeter (mm) 10mm = 1cm = 0.3937 in inch (in) 12 in = 1 ft = 0.3048 m
centimeter (cm) 10cm = 1dm = 3.937 in foot (ft) 3 ft = 1 yd = 0.9144 m
decimeter (dm) 10dm = 1 m = 3.2808 ft yard (yd) 5 1/2 yd = 16 1/2 ft = 5.029 m
meter (m) 10m = 1 dam = 32.808 ft mile (mi) 1 mi = 5,280 ft
dekameter (dam) 10dam = 1hm = 328.08 ft
hectometer (hm) 10hm = 1km = 0.621 mi

Metric Weight Equivalents

Metric English
milligram (mg) 10 mg = 1 cg = 0.1543 gr grain 1 gr = 0.0648 g
centigram (cg) 10 cg = 1 dg = 1.5432 gr ounce 1 oz = 28.3495 g
decigram (dg) 10 dg = 1 gm = 15.432 gr pound 1 lb = 16 oz = 0.4536 kg
gram (g) 10 g = 1 dg = 0.35274 oz
dekagram (dag) 10 dg = 1 hg = 3.5274 oz
hectogram (hg) 10 hg = 1 kg = 2.2046 lb
kilogram (kg) 1,000 kg = 2,204.6 lb