---
mapped_pages:
  - https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket.html
---

# Bucket [search-aggregations-bucket]

Bucket aggregations don’t calculate metrics over fields like the metrics aggregations do, but instead, they create buckets of documents. Each bucket is associated with a criterion (depending on the aggregation type) which determines whether or not a document in the current context "falls" into it. In other words, the buckets effectively define document sets. In addition to the buckets themselves, the `bucket` aggregations also compute and return the number of documents that "fell into" each bucket.

Bucket aggregations, as opposed to `metrics` aggregations, can hold sub-aggregations. These sub-aggregations will be aggregated for the buckets created by their "parent" bucket aggregation.

There are different bucket aggregators, each with a different "bucketing" strategy. Some define a single bucket, some define fixed number of multiple buckets, and others dynamically create the buckets during the aggregation process.

::::{note}
The [`search.max_buckets`](/reference/elasticsearch/configuration-reference/search-settings.md#search-settings-max-buckets) cluster setting limits the number of buckets allowed in a single response.
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