Fixed Size

Fixed arrays have a fixed size which cannot be changed at run-time.
These are also known as Static Arrays.
An array is declared by including parentheses after the array name or identifier.
An integer is placed within the parentheses, defining the number of elements in the array.

Explicit Lower Bound

It is possible to explicitly declare the lower bound of your array.
The following two lines are equivalent and both these arrays contain 101 elements.
The index values range from 0 to 100.

Dim myArray(100) As Integer 
Dim myArray(0 to 100) As Integer 

If you wanted to declare an array containing exactly 100 elements you could do this in a number of different ways.

Dim myArray(99) As Integer 
Dim myArray(0 to 99) As Integer 
Dim myArray(1 to 100) As Integer 

The first two lines are equivalent. The first element is myArray(0) and the last element is myArray(99).
The last line has slightly different index numbers. The first element is myArray(1) and the last element is myArray(100).
In fact you could define the index numbers to be any range you like as long as the first number is less than the second number.

Dim myArray(101 to 200) As Integer 
Dim myArray(-49 to 50) As Integer 

When you explicitly declare the lower bound of your array this will override the Option Base statement.

Option Base Statement

If you want all your arrays to start at the index number 1 (instead of 0) you can define a module level setting.
The following line of code will declare an array containing exactly 100 elements with the index values from 1 to 100.
Notice that we have not explicitly declared the lower bound to be 1.

Option Base 1 
Dim myArray(100) As Integer 

More details can be found on the Option Base 1 page.

Important

For more details about using Excel Ranges with arrays, refer to the Excel > Cells & Ranges > VBA Code > Working with Arrays page.