> ## 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="str" required>
  The key to get.
</ParamField>

<ParamField body="start" type="int">
  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="int">
  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="int" required>
  The number of set bits in the specified range.
</ResponseField>

<RequestExample>
  ```py Example theme={"system"}
  redis.setbit("mykey", 7, 1)
  redis.setbit("mykey", 8, 1)
  redis.setbit("mykey", 9, 1)

  # With range
  assert redis.bitcount("mykey", 0, 10) == 3

  # Without range
  assert redis.bitcount("mykey") == 3
  ```
</RequestExample>