Each variable has a type: Long for whole numbers, Double for decimals, String for text, Boolean for True/False, Date for dates and times, and Variant for anything. Picking the right type prevents overflow and conversion bugs.

Code

Dim count As Long
Dim price As Double
Dim ok As Boolean

• Common types

  Dim count As Long Dim price As Double Dim ok As Boolean → Whole number, decimal, flag

  The three most used.

• Why Long, not Integer

  Dim n As Integer n = 40000 ' overflow error → Integer tops out at 32,767

  Use Long instead.

• Dates

  Dim d As Date d = DateSerial(2025, 3, 15) → A real date

  Date math works on it.

• Use Long, not Integer. Integer overflows at 32,767.
• Long has no speed penalty over Integer on modern Excel.
• Currency holds money to four decimals without floating-point drift.
• Convert explicitly with CLng, CDbl, CStr rather than relying on implicit conversion.

• Integer overflow at 32,767 is a runtime error 6.
• Doubles can show 0.1 + 0.2 as 0.30000000000000004; round for display.