---
title: influxdb.cardinality() function
description: >
  `influxdb.cardinality()` returns the series cardinality of data retrieved from InfluxDB.
menu:
  flux_v0_ref:
    name: influxdb.cardinality
    parent: influxdata/influxdb
    identifier: influxdata/influxdb/cardinality
weight: 201
flux/v0/tags: [metadata]
introduced: 0.92.0
---

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`influxdb.cardinality()` returns the series cardinality of data retrieved from InfluxDB.


{{% note %}}
Although this function is similar to InfluxQL's [`SHOW SERIES CARDINALITY`](/influxdb/v1/query_language/spec/#show-series-cardinality),
it works in a slightly different manner.

`influxdb.cardinality()` is time bounded and reports the cardinality of data that matches the conditions passed into it rather than that of the bucket as a whole.
{{% /note %}}


##### Function type signature

```js
(
    start: A,
    ?bucket: string,
    ?bucketID: string,
    ?host: string,
    ?org: string,
    ?orgID: string,
    ?predicate: (r: {B with _value: C, _measurement: string, _field: string}) => bool,
    ?stop: D,
    ?token: string,
) => stream[{_value: int, _stop: time, _start: time}] where A: Timeable, D: Timeable
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### bucket

Bucket to query cardinality from.



### bucketID

String-encoded bucket ID to query cardinality from.



### org

Organization name.



### orgID

String-encoded organization ID.



### host

URL of the InfluxDB instance to query.

See [InfluxDB Cloud regions](/influxdb/cloud/reference/regions/)
or [InfluxDB OSS URLs](/influxdb/v2/reference/urls/).

### token

InfluxDB API token.



### start
({{< req >}})
Earliest time to include when calculating cardinality.

The cardinality calculation includes points that match the specified start time.
Use a relative duration or absolute time. For example, `-1h` or `2019-08-28T22:00:00Z`.
Durations are relative to `now()`.

### stop

Latest time to include when calculating cardinality.

The cardinality calculation excludes points that match the specified start time.
Use a relative duration or absolute time. For example, `-1h` or `2019-08-28T22:00:00Z`.
Durations are relative to `now()`. Default is `now()`.

{{% note %}}
The default value is `now()`, so any points that have been written into the future will
not be counted unless a future `stop` date is provided.
{{% /note %}}


### predicate

Predicate function that filters records.
Default is `(r) => true`.




## Examples

- [Query series cardinality in a bucket](#query-series-cardinality-in-a-bucket)
- [Query series cardinality in a measurement//](#query-series-cardinality-in-a-measurement)
- [Query series cardinality for a specific tag](#query-series-cardinality-for-a-specific-tag)
- [Query series cardinality of Data Written In the Last 4 Hours](#query-series-cardinality-of-data-written-in-the-last-4-hours)

### Query series cardinality in a bucket

```js
import "influxdata/influxdb"

influxdb.cardinality(bucket: "example-bucket", start: time(v: 1))

```
Note: if points have been written into the future, you will need to add an appropriate `stop` date


### Query series cardinality in a measurement//

```js
import "influxdata/influxdb"

influxdb.cardinality(
    bucket: "example-bucket",
    start: time(v: 1),
    predicate: (r) => r._measurement == "example-measurement",
)

```


### Query series cardinality for a specific tag

```js
import "influxdata/influxdb"

influxdb.cardinality(bucket: "example-bucket", start: time(v: 1), predicate: (r) => r.exampleTag == "foo")

```


### Query Cardinality of Data Written In the Last 4 hours
```js
import "influxdata/influxdb"

influxdb.cardinality(bucket: "example-bucket", start: -4h)

```