# Par size

#### avkid

##### Not a New User
Fight Leukemia
What data is used to calculate the size of a par can?

#### digitaltec

##### Active Member
Risk of electrical shock!

I believe it is something to do with diameter.

#### propmonkey

##### Well-Known Member
its measured in how many 8ths of an inch across the lense is, therefore a PAR 64 has a diameter of 8 inches.

d=(par#) * (.125)

#### len

##### Well-Known Member
You can also spec the size of the lamp to some degree in the larger units, and the type of focus, from (and I forgot the exact specs, but they're out there) very narrow to wide, or something.