The US Measurement system for length is comprised of 4 standard units of measurement.
These units are the inch, foot, yard and mile.

The inch unit (inches plural) is internationally recognized by its abbreviation or symbol "in."
However, the inch may also be denoted by a double prime symbol ( ″ ) or a double quotation mark ( " )
1 inch may appear as 1 in, 1″ or 1"
The inch is 1/12th of a foot and is 1/36th of a yard in length.
Internationally the inch is 0.0254 m, 25.4 mm or 2.54 cm.
In typography 1 inch equals 72 pt. or points.

The foot unit (feet plural) is internationally recognized by its abbreviation or symbol "ft."
However, the foot may also be denoted by a prime symbol ( ′ ) or an apostrophe ( ' )
1 foot may appear as 1 ft, 1′ or 1'
The foot is comprised of 12 inches and is 1/3rd of a yard in length.
Internationally the foot is 0.3048 m, 304.8 mm or 30.48 cm.

The yard unit (yards plural and abbreviated "yd") is comprised of 36 inches, or is exactly 3 feet in length.
Internationally the yard is equal to 0.9144 m, 914.4 mm or 91.44 cm.

The mile unit (miles plural and is currently abbreviated "mi") is comprised of 5,280 feet, or 1,760 yards in length.
The mile that is comprised of 5,280 feet is often recognized and denoted as a Statute Mile or a Land Mile.
This is to help distinguish it from the Nautical Mile (6,076.1 ft or 1,852 m.)
Internationally the mile is equal to 1,609.344 m or 1.609344 km.

Here's a Height Cheat Sheet to make things easier.

1 in = 72 pt. 0.0254 m, 25.40 mm or 2.54 cm.
2 in = 0.0508 m, 50.80 mm or 5.08 cm.
3 in = 0.0762 m, 76.20 mm or 7.62 cm.
4 in = 0.1016 m, 101.60 mm or 10.16 cm.
5 in = 0.1270 m, 127.00 mm or 12.70 cm.
6 in = 0.1524 m, 152.40 mm or 15.24 cm.
7 in = 0.1778 m, 177.80 mm or 17.78 cm.
8 in = 0.2032 m, 203.20 mm or 20.32 cm.
9 in = 0.2286 m, 228.60 mm or 22.86 cm.
10 in = 0.2540 m, 254.00 mm or 25.40 cm.
11 in = 0.2794 m, 279.40 mm or 27.94 cm.
12 in or 1 ft. and 0 in (1'0") = 0.3048 m, 304.80 mm or 30.48 cm.
13 in or 1 ft. and 1 in (1'1") = 0.3348 m, 330.20 mm or 33.02 cm.
14 in or 1 ft. and 2 in (1'2") = 0.3556 m, 355.60 mm or 35.56 cm.
15 in or 1 ft. and 3 in (1'3") = 0.3810 m, 381.00 mm or 38.10 cm.
16 in or 1 ft. and 4 in (1'4") = 0.4064 m, 406.40 mm or 40.64 cm.
17 in or 1 ft. and 5 in (1'5") = 0.4318 m, 431.80 mm or 43.18 cm.
18 in or 1 ft. and 6 in (1'6") = 0.4572 457.20 mm or 45.72 cm.
19 in or 1 ft. and 7 in (1'7") = 0.4826 482.60 mm or 48.26 cm.
20 in or 1 ft. and 8 in (1'8") = 0.5080 508.00 mm or 50.80 cm.
21 in or 1 ft. and 9 in (1'9") = 0.5334 533.40 mm or 53.34 cm.
22 in or 1 ft. and 10 in (1'10") = 0.5588 558.80 mm or 55.88 cm.
23 in or 1 ft. and 11 in (1'11") = 0.5842 584.20 mm or 58.42 cm.
24 in or 2 ft. and 0 in (2'0") = 0.6046 m, 609.60 mm or 60.96 cm.
25 in or 2 ft. and 1 in (2'1") = 0.6350 m, 635.00 mm or 63.50 cm.
26 in or 2 ft. and 2 in (2'2") = 0.6604 m, 660.40 mm or 66.04 cm.
27 in or 2 ft. and 3 in (2'3") = 0.6858 m, 685.80 mm or 68.58 cm.
28 in or 2 ft. and 4 in (2'4") = 0.7112 m, 711.20 mm or 71.12 cm.
29 in or 2 ft. and 5 in (2'5") = 0.7366 m, 736.60 mm or 73.66 cm.
30 in or 2 ft. and 6 in (2'6") = 0.7620 m, 762.00 mm or 76.20 cm.
31 in or 2 ft. and 7 in (2'7") = 0.7874 m, 787.40 mm or 78.74 cm.
32 in or 2 ft. and 8 in (2'8") = 0.8128 m, 812.80 mm or 81.28 cm.
33 in or 2 ft. and 9 in (2'9") = 0.8382 m, 838.20 mm or 83.82 cm.
34 in or 2 ft. and 10 in (2'10") = 0.8636 m, 863.60 mm or 86.36 cm.
35 in or 2 ft. and 11 in (2'11") = 0.8890 m, 889.00 mm or 88.90 cm.
36 in or 3 ft. and 0 in (3'0") = 1 yd, 0.9144 m, 914.40 mm or 91.44 cm.
37 in or 3 ft. and 1 in (3'1") = 0.9398 m, 939.80 mm or 93.98 cm.
38 in or 3 ft. and 2 in (3'2") = 0.9652 m, 965.20 mm or 96.52 cm.
39 in or 3 ft. and 3 in (3'3") = 0.9906 m, 990.60 mm or 99.06 cm.
40 in or 3 ft. and 4 in (3'4") = 1.0160 m, 1016.00 mm or 101.60 cm.
41 in or 3 ft. and 5 in (3'5") = 1.0414 m, 1041.40 mm or 104.14 cm.
42 in or 3 ft. and 6 in (3'6") = 1.0688 m, 1068.80 mm or 106.88  cm.
43 in or 3 ft. and 7 in (3'7") = 1.0922 m, 1092.20 mm or 109.22 cm.
44 in or 3 ft. and 8 in (3'8") = 1.1176 m, 1117.60 mm or 111.76 cm.
45 in or 3 ft. and 9 in (3'9") = 1.1430 m, 1143.00 mm or 114.30 cm.
46 in or 3 ft. and 10 in (3'10") = 1.1684 m, 1168.40 mm or 116.84 cm.
47 in or 3 ft. and 11 in (3'11") = 1.1938 m, 1193.80 mm or 119.38 cm.
48 in or 4 ft. and 0 in (4'0") = 1.2192 m, 1219.20 mm or 121.92 cm.
49 in or 4 ft. and 1 in (4'1") = 1.2446 m, 1244.60 mm or 124.46 cm.
50 in or 4 ft. and 2 in (4'2") = 1.2700 m, 1270.00 mm or 127.00 cm.
51 in or 4 ft. and 3 in (4'3") = 1.2954 m, 1295.40 mm or 129.54 cm.
52 in or 4 ft. and 4 in (4'4") = 1.3208 m, 1320.80 mm or 132.08 cm.
53 in or 4 ft. and 5 in (4'5") = 1.3462 m, 1346.20 mm or 134.62 cm.
54 in or 4 ft. and 6 in (4'6") = 1.3716 m, 1371.60 mm or 137.16 cm.
55 in or 4 ft. and 7 in (4'7") = 1.3970 m, 1397.00 mm or 139.70 cm.
56 in or 4 ft. and 8 in (4'8") = 1.4224 m, 1422.40 mm or 142.24 cm.
57 in or 4 ft. and 9 in (4'9") = 1.4478 m, 1447.80 mm or 144.78 cm.
58 in or 4 ft. and 10 in (4'10") = 1.4732 m, 1473.20 mm or 147.32 cm.
59 in or 4 ft. and 11 in (4'11") = 1.4986 m, 1498.60 mm or 149.86 cm.
60 in or 5 ft. and 0 in (5'0") = 1.5240 m, 1524.00 mm or 152.40 cm.
61 in or 5 ft. and 1 in (5'1") = 1.5494 m, 1549.40 mm or 154.94 cm.
62 in or 5 ft. and 2 in (5'2") = 1.5748 m, 1574.80 mm or 157.48 cm.
63 in or 5 ft. and 3 in (5'3") = 1.6002 m, 1600.20 mm or 160.02 cm.
64 in or 5 ft. and 4 in (5'4") = 1.6256 m, 1625.60 mm or 162.56 cm.
65 in or 5 ft. and 5 in (5'5") = 1.6510 m, 1651.00 mm or 165.10 cm.
66 in or 5 ft. and 6 in (5'6") = 1.6764 m, 1676.40 mm or 167.64 cm.
67 in or 5 ft. and 7 in (5'7") = 1.7018 m, 1701.80 mm or 170.18 cm.
68 in or 5 ft. and 8 in (5'8") = 1.7272 m, 1727.20 mm or 172.72 cm.
69 in or 5 ft. and 9 in (5'9") = 1.7526 m, 1752.60 mm or 175.26 cm.
70 in or 5 ft. and 10 in (5'10") = 1.7780 m, 1778.00 mm or 177.80 cm.
71 in or 5 ft. and 11 in (5'11") = 1.8034 m, 1803.40 mm or 180.34 cm.
72 in or 6 ft. and 0 in (6'0") = 1.8288 m, 1828.80 mm or 182.88 cm.
73 in or 6 ft. and 1 in (6'1") = 1.8542 m, 1854.20 mm or 185.42 cm.
74 in or 6 ft. and 2 in (6'2") = 1.8796 m, 1879.60 mm or 187.96 cm.
75 in or 6 ft. and 3 in (6'3") = 1.9050 m, 1905.00 mm or 190.5 cm.
76 in or 6 ft. and 4 in (6'4") = 1.9304 m, 1930.40 mm or 193.04 cm.
77 in or 6 ft. and 5 in (6'5") = 1.9558 m, 1955.80 mm or 195.58 cm.
78 in or 6 ft. and 6 in (6'6") = 1.9812 m, 1981.20 mm or 198.12 cm.
79 in or 6 ft. and 7 in (6'7") = 2.0066 m, 2006.60 mm or 200.66 cm.
80 in or 6 ft. and 8 in (6'8") = 2.0320 m, 2032.00 mm or 203.20 cm.
81 in or 6 ft. and 9 in (6'9") = 2.0574 m, 2057.40 mm or 205.74 cm.
82 in or 6 ft. and 10 in (6'10") = 2.0828 m, 2082.80 mm or 208.28 cm.
83 in or 6 ft. and 11 in (6'11") = 2.1082 m, 2108.20 mm or 210.82 cm.
84 in or 7 ft. and 0 in (7'0") = 2.1336 m, 2133.60 mm or 213.36 cm.

A weight conversion tutorial will be coming soon.