> ## 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.

# HyperLogLog commands

> Commands for probabilistic cardinality estimation.

> [card] [PFADD](https://upstash.com/docs/redis/commands/hyperloglog/pfadd)
>
> Add elements to HyperLogLog

> [card] [PFCOUNT](https://upstash.com/docs/redis/commands/hyperloglog/pfcount)
>
> Get estimated cardinality

> [card] [PFMERGE](https://upstash.com/docs/redis/commands/hyperloglog/pfmerge)
>
> Merge multiple HyperLogLogs


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