VBA Data Types and Limits
A Boolean is used to store values that can be represented as either True or False. Internally, the data type is stored as a 16 bit value with 0 representing False and any other value representing True.
It should be noted that when a Boolean is cast to a numeric type, all of the bits are set to 1. This results in an internal representation of -1 for signed types and the maximum value for an unsigned type (Byte).
The casting function to convert to a Boolean is CBool(). Even though it is represented internally as a 16 bit number,
casting to a Boolean from values outside of that range is safe from overflow, although it sets all 16 bits to 1: