# Numeric Data Types

**Visual Studio 2005**

Visual Basic supplies several *numeric data types* for handling numbers in various representations. *Integral* types represent only whole numbers (positive, negative, and zero), and *nonintegral* types represent numbers with both integer and fractional parts.

For a table showing a side-by-side comparison of the Visual Basic data types, see Data Type Summary (Visual Basic).

# Integral Numeric Types

*Integral data types* are those that represent only numbers without fractional parts.

The *signed* integral data types are SByte Data Type (Visual Basic) (8-bit), Short Data Type (Visual Basic) (16-bit), Integer Data Type (Visual Basic) (32-bit), and Long Data Type (Visual Basic) (64-bit). If a variable always stores integers rather than fractional numbers, declare it as one of these types.

The *unsigned* integral types are Byte Data Type (Visual Basic) (8-bit), UShort Data Type (Visual Basic) (16-bit), UInteger Data Type (32-bit), and ULong Data Type (Visual Basic) (64-bit). If a variable contains binary data, or data of unknown nature, declare it as one of these types.

### Performance

Arithmetic operations are faster with integral types than with other data types. They are fastest with the **Integer** and **UInteger** types in Visual Basic.

### Large Integers

If you need to hold an integer larger than the **Integer** data type can hold, you can use the **Long** data type instead. **Long** variables can hold numbers from -9,223,372,036,854,775,808 through 9,223,372,036,854,775,807. Operations with **Long** are slightly slower than with **Integer**.

If you need even larger values, you can use the Decimal Data Type (Visual Basic). You can hold numbers from -79,228,162,514,264,337,593,543,950,335 through 79,228,162,514,264,337,593,543,950,335 in a **Decimal** variable if you do not use any decimal places. However, operations with **Decimal** numbers are considerably slower than with any other numeric data type.

### Small Integers

If you do not need the full range of the **Integer** data type, you can use the **Short** data type, which can hold integers from -32,768 through 32,767. For the smallest integer range, the **SByte** data type holds integers from -128 through 127. If you have a very large number of variables that hold small integers, the common language runtime can sometimes store your **Short** and **SByte** variables more efficiently and save memory consumption. However, operations with **Short** and **SByte** are somewhat slower than with **Integer**.

### Unsigned Integers

If you know that your variable never needs to hold a negative number, you can use the *unsigned types* **Byte**, **UShort**, **UInteger**, and **ULong**. Each of these data types can hold a positive integer twice as large as its corresponding signed type (**SByte**, **Short**, **Integer**, and **Long**). In terms of performance, each unsigned type is exactly as efficient as its corresponding signed type. In particular, **UInteger** shares with **Integer** the distinction of being the most efficient of all the elementary numeric data types.

# Nonintegral Numeric Types

*Nonintegral data types* are those that represent numbers with both integer and fractional parts.

The nonintegral numeric data types are **Decimal** (128-bit fixed point), Single Data Type (Visual Basic) (32-bit floating point), and Double Data Type (Visual Basic) (64-bit floating point). They are all signed types. If a variable can contain a fraction, declare it as one of these types.

**Decimal** is not a floating-point data type. **Decimal** numbers have a binary integer value and an integer scaling factor that specifies what portion of the value is a decimal fraction.

Floating-point (**Single** and **Double**) numbers have larger ranges than **Decimal** numbers but can be subject to rounding errors. Floating-point types support fewer significant digits than **Decimal** but can represent values of greater magnitude.

Nonintegral number values can be expressed as *mmmEeee*, in which *mmm* is the *mantissa* (the significant digits) and *eee* is the *exponent* (a power of 10). The highest positive values of the nonintegral types are 7.9228162514264337593543950335E+28 for **Decimal**, 3.4028235E+38 for **Single**, and 1.79769313486231570E+308 for **Double**.

### Performance

**Double** is the most efficient of the fractional data types, because the processors on current platforms perform floating-point operations in double precision. However, operations with **Double** are not as fast as with the integral types such as **Integer**.

### Small Magnitudes

For numbers with the smallest possible magnitude (closest to 0), **Double** variables can hold numbers as small as -4.94065645841246544E-324 for negative values and 4.94065645841246544E-324 for positive values.

### Small Fractional Numbers

If you do not need the full range of the **Double** data type, you can use the **Single** data type, which can hold floating-point numbers from -3.4028235E+38 through 3.4028235E+38. The smallest magnitudes for **Single** variables are -1.401298E-45 for negative values and 1.401298E-45 for positive values. If you have a very large number of variables that hold small floating-point numbers, the common language runtime can sometimes store your **Single** variables more efficiently and save memory consumption.

# See Also

#### Tasks

Troubleshooting Data TypesHow to: Hold Integers in a Variable

How to: Hold Fractions in a Variable

How to: Hold the Largest Possible Number in a Variable

How to: Optimize Storage of Positive Integers With Unsigned Types

How to: Call a Windows Function that Takes Unsigned Types

How to: Hold the Most Significant Digits in a Variable

How to: Hold Money Values in a Variable

#### Concepts

Character Data TypesMiscellaneous Data Types