Weight of mild steel round bars can be calculated as

W = 0.0062 d²                            (1) 

where 

W = weight (kg/m)

d = round diameter (mm)

Bar Diameter (mm)	Weight (kg/m)
6	0.22
8	0.39
10	0.62
12	0.89
16	1.58
20	2.47
25	3.85
32	6.31
40	9.86
45	12.5
50	15.4
60	22.2
65	26.0
75	34.7
90	49.9
100	61.6