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float and real (Transact-SQL)

Approximate-number data types for use with floating point numeric data. Floating point data is approximate; therefore, not all values in the data type range can be represented exactly.

Note

The ISO synonym for real is float(24).

Data type

Range

Storage

float

- 1.79E+308 to -2.23E-308, 0 and 2.23E-308 to 1.79E+308

Depends on the value of n

real

- 3.40E + 38 to -1.18E - 38, 0 and 1.18E - 38 to 3.40E + 38

4 Bytes

Topic link iconTransact-SQL Syntax Conventions

Syntax

  • float [ (n) ]
    Where n is the number of bits that are used to store the mantissa of the float number in scientific notation and, therefore, dictates the precision and storage size. If n is specified, it must be a value between 1 and 53. The default value of n is 53.

    nvalue

    Precision

    Storage size

    1-24

    7 digits

    4 bytes

    25-53

    15 digits

    8 bytes

Note

SQL Server treats n as one of two possible values. If 1<=n<=24, n is treated as 24. If 25<=n<=53, n is treated as 53.

The SQL Server float[(n)] data type complies with the ISO standard for all values of n from 1 through 53. The synonym for double precision is float(53).