Hex to Diameter Calculator

Here's a Hex Size to Diameter Conversion Table, which provides the relationship between the across-flats (AF) measurement of a hexagonal shape and the corresponding diameter (circumscribed circle diameter, CD):

Hex Size (Across Flats)	Circumscribed Circle Diameter (CD)
1 mm	1.155 mm
2 mm	2.309 mm
3 mm	3.464 mm
4 mm	4.618 mm
5 mm	5.773 mm
6 mm	6.928 mm
7 mm	8.083 mm
8 mm	9.237 mm
9 mm	10.392 mm
10 mm	11.547 mm
11 mm	12.701 mm
12 mm	13.856 mm
13 mm	15.011 mm
14 mm	16.166 mm
15 mm	17.320 mm
16 mm	18.475 mm
17 mm	19.630 mm
18 mm	20.785 mm
19 mm	21.939 mm
20 mm	23.094 mm
25 mm	28.868 mm
30 mm	34.641 mm
35 mm	40.415 mm
40 mm	46.188 mm

Formula Used:

To calculate the circumscribed circle diameter (CD):