+ Operator

This page is specific to the Visual Basic for Applications (VBA) Language Reference for Office 2010.

Used to sum two numbers.

Syntax

result = expression1+expression2

The + operator syntax has these parts:

Part	Description
result	Required; any numeric variable.
expression1	Required; any expression.
expression2	Required; any expression.

Remarks

When you use the + operator, you may not be able to determine whether addition or string concatenation will occur. Use the & operator for concatenation to eliminate ambiguity and provide self-documenting code.

If at least one expression is not a Variant, the following rules apply:

If	Then
Both expressions are numeric data types (Byte, Boolean, Integer, Long, Single, Double, Date, Currency, or Decimal)	Add.
Both expressions are String	Concatenate.
One expression is a numeric data type and the other is any Variant except Null	Add.
One expression is a String and the other is any Variant except Null	Concatenate.
One expression is an EmptyVariant	Return the remaining expression unchanged as result.
One expression is a numeric data type and the other is a String	A Type mismatch error occurs.
Either expression is Null	result is Null.

If both expressions are Variant expressions, the following rules apply:

If	Then
Both Variant expressions are numeric	Add.
Both Variant expressions are strings	Concatenate.
One Variant expression is numeric and the other is a string	Add.

For simple arithmetic addition involving only expressions of numeric data types, the data type of result is usually the same as that of the most precise expression. The order of precision, from least to most precise, is Byte, Integer, Long, Single, Double, Currency, and Decimal. The following are exceptions to this order:

If	Then result is
A Single and a Long are added,	a Double.
The data type of result is a Long, Single, or Date variant that overflows its legal range,	converted to a Double variant.
The data type of result is a Byte variant that overflows its legal range,	converted to an Integer variant.
The data type of result is an Integer variant that overflows its legal range,	converted to a Long variant.
A Date is added to any data type,	a Date.

If one or both expressions are Null expressions, result is Null. If both expressions are Empty, result is an Integer. However, if only one expression is Empty, the other expression is returned unchanged as result.

Note

The order of precision used by addition and subtraction is not the same as the order of precision used by multiplication.

Example

This example uses the + operator to sum numbers. The + operator can also be used to concatenate strings. However, to eliminate ambiguity, you should use the & operator instead. If the components of an expression created with the + operator include both strings and numerics, the arithmetic result is assigned. If the components are exclusively strings, the strings are concatenated.

Dim MyNumber, Var1, Var2
MyNumber = 2 + 2    ' Returns 4.
MyNumber = 4257.04 + 98112    ' Returns 102369.04.

Var1 = "34": Var2 = 6    ' Initialize mixed variables.
MyNumber = Var1 + Var2    ' Returns 40.

Var1 = "34": Var2 = "6"    ' Initialize variables with strings.
MyNumber = Var1 + Var2    ' Returns "346" (string concatenation).