Milliken suggests the following table linen sizes for standard table sizes.

Table Size Suggested Tablecloth Size Table Size Suggested Tablecloth Size
24 x 24
41 x 41 (8)
42 x 42
61 x 61 (9)
24 x 30
41 x 47 (8)
42 x 48
61 x 67 (9)
24 x 36
41 x 53 (8)
42 x 60
61 x 79 (9)
24 x 42
41 x 59 (8)
42 x 72
61 x 91 (9)
30 x 30
52 x 52 (10)
42 x 84
61 x 103 (9)
30 x 36
52 x 58 (10)
42 x 96
61 x 117 (9)
30 x 42
52 x 64 (10)
42 x 108
61 x 127 (9)
30 x 45
52 x 67 (10)
48 x 48
71 x 71 (9 1/2)
30 x 48
52 x 70 (10)
30" Rnd
51" Dia (10)
30 x 72
52 x 94 (10)
36" Rnd
51 Dia (7)
30 x 84
52 x 107 (10)
42" Rnd
60" Dia (8)
30 x 96
52 x 118 (10)
48" Rnd
70" Dia (9 1/2)
36 x 36
52 x 52 (7 1/2)
51" Rnd
70" Dia (8)
36 x 42
52 x 58 (7 1/2)
54" Rnd
70" Dia (7 1/2)
36 x 48
52 x 64 (7 1/2)
60" Rnd
80" Dia (9)
36 x 72
52 x 88 (7 1/2)
66" Rnd
89" Dia (10 1/2)
36 x 96
52 x 112 (7 1/2)
72" Rnd
89" Dia (7 1/2)

Note: The tablecloth sizes suggested are cut sizes. The number in parentheses indicates the drop in inches. If you want a larger or shorter drop, then the table cloth size needs to be modified to accommodate the look you want to achieve.