---
title: "BIT_COUNT (Transact-SQL)"
description: "Transact-SQL reference for the BIT_COUNT function."
author: thesqlsith
ms.author: derekw
ms.reviewer: randolphwest
ms.date: 02/03/2025
ms.service: sql
ms.subservice: t-sql
ms.topic: reference
f1_keywords:
  - "BIT_COUNT"
  - "BIT_COUNT_TSQL"
helpviewer_keywords:
  - "bit manipulation [SQL Server], bit count"
  - "BIT_COUNT function"
  - "bit shifting [SQL Server], bit count"
dev_langs:
  - "TSQL"
monikerRange: ">=sql-server-ver16 || >=sql-server-linux-ver16 || =azuresqldb-mi-current || =azuresqldb-current || =fabric"
---
# BIT_COUNT (Transact SQL)

[!INCLUDE [SQL Server 2022, SQL Database, SQL Managed Instance FabricSE FabricDW](../../includes/applies-to-version/sqlserver2022-asdb-asmi-fabricse-fabricdw.md)]

`BIT_COUNT` takes one parameter and returns the number of bits set to 1 in that parameter as a **bigint** type.

:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: [Transact-SQL syntax conventions](../../t-sql/language-elements/transact-sql-syntax-conventions-transact-sql.md)

## Syntax

```syntaxsql
BIT_COUNT ( expression_value )
```

## Arguments

#### *expression_value*

Any integer or binary expression that isn't a large object ([LOB](#remarks)).

## Return types

**bigint**

`BIT_COUNT` doesn't cast, before counting the number of bits. This is because the same number can have a different number of ones in its binary representation depending on the data type.

For example, `SELECT BIT_COUNT (CAST (-1 AS SMALLINT))` and `SELECT BIT_COUNT (CAST (-1 AS INT))` return `16` and `32` respectively. This is intended, as the binary representation of `-1` can have a different number of bits set to `1` depending on the data type.

## Remarks

Distributed Query functionality for the bit manipulation functions within linked server or ad hoc queries (`OPENQUERY`) aren't supported.

Large object (LOB) data types in the Database Engine can store data that exceeds 8,000 bytes. These data types store data on a [row-overflow](../../relational-databases/pages-and-extents-architecture-guide.md#row-overflow-considerations) data page. A LOB also encompasses data types that store data on dedicated LOB page structures, which use a text or an image pointer of in-row references to LOB data pages. For more information about data storage, see the [Pages and extents architecture guide](../../relational-databases/pages-and-extents-architecture-guide.md).

The bit manipulation functions operate on the **tinyint**, **smallint**, **int**, **bigint**, **binary(*n*)**, and **varbinary(*n*)** data types. Large object (LOB) data types, such as **varchar(max)**, **nvarchar(max)**, **varbinary(max)**, **image**, **ntext**, **text**, **xml**, and common language runtime (CLR) BLOB types, aren't supported.

## Examples

#### A. Calculate the BIT_COUNT in a binary value

In the following example, the number of bits set to `1` in a binary value are calculated.

```sql
SELECT BIT_COUNT(0xabcdef) AS Count;
```

The result is `17`. This is because `0xabcdef` in binary is `1010 1011 1100 1101 1110 1111`, and there are 17 bits with a value set to `1`.

#### B. Calculate the BIT_COUNT in an integer

In the following example, the number of bits set to `1` in an integer are calculated.

```sql
SELECT BIT_COUNT(17) AS Count;
```

The result is `2`. This is because `17` in binary is `0001 0001`, and there are only 2 bits with a value set to `1`.

## Related content

- [LEFT_SHIFT (Transact SQL)](left-shift-transact-sql.md)
- [RIGHT_SHIFT (Transact SQL)](right-shift-transact-sql.md)
- [SET_BIT (Transact SQL)](set-bit-transact-sql.md)
- [GET_BIT (Transact SQL)](get-bit-transact-sql.md)
- [Bit manipulation functions](bit-manipulation-functions-overview.md)