There are 2 ways to add zeroes to a number in Kotlin.
String.format()
This method returns a string obtained by substituting the specified arguments, using the default locale.
val monthOfYear = 2 val numberWithLeadingZero = String.format("%02d", monthOfYear) println(numberWithLeadingZero) // "02"
CharSequence.padStart()
This method returns a char sequence with content of this char sequence padded at the beginning to the specified length with the specified character or space.
val padWithZeros = "5".padStart(2, '0') println(padWithZeros) // "05"