For local badges, a user earns level 1 of the badge with their very first check in. After their first check in, a new level is reached with every subsequent five check ins. For example, it takes six total check ins to reach level 2, 11 check ins to reach level 3, etc. There's a simple formula you can use:
To calculate how many check-ins are at Level X, use the following formula:
(Badge Level x 5) - 4
For example, how many check-ins are needed to earn level 20?
(20 x 5) - 4 = 96 check-ins!