> ## Documentation Index
> Fetch the complete documentation index at: https://upstash.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# BITCOUNT

> Count the number of set bits.

The `BITCOUNT` command in Redis is used to count the number of set bits (bits with a value of 1) in a range of bytes within a key that is stored as a binary string. It is primarily used for bit-level operations on binary data stored in Redis.

## Arguments

<ParamField body="key" type="string" required>
  The key to get.
</ParamField>

<ParamField body="start" type="integer">
  Specify the range of bytes within the binary string to count the set bits. If not provided, it counts set bits in the entire string.

  Either specify both `start` and `end` or neither.
</ParamField>

<ParamField body="end" type="integer">
  Specify the range of bytes within the binary string to count the set bits. If not provided, it counts set bits in the entire string.

  Either specify both `start` and `end` or neither.
</ParamField>

## Response

<ResponseField type="integer" required>
  The number of set bits in the specified range.
</ResponseField>

<RequestExample>
  ```ts Example theme={"system"}
  const bits = await redis.bitcount(key);
  ```

  ```ts With Range theme={"system"}
  const bits = await redis.bitcount(key, 5, 10);
  ```
</RequestExample>