> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# db.collection.totalIndexSize() (mongosh method)

**Important: mongosh Method**

This page documents a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) method. This is *not* the documentation for database commands or language-specific drivers, such as Node.js.

For the database command, see the [`totalIndexSize`](https://www.mongodb.com/docs/manual/reference/command/collstats.md#mongodb-data-collStats.totalIndexSize) field returned
by the [`collStats`](https://www.mongodb.com/docs/manual/reference/command/collstats.md#mongodb-dbcommand-dbcmd.collStats) command.

For MongoDB API drivers, refer to the language-specific [MongoDB driver documentation.](https://www.mongodb.com/docs/drivers/)

## Definition

The total size of all indexes for the collection.

If an index uses prefix compression (which is the [`default for WiredTiger`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--wiredTigerIndexPrefixCompression)), the returned size reflects the compressed size.

To run on a replica set member, [`collStats`](https://www.mongodb.com/docs/manual/reference/command/collstats.md#mongodb-dbcommand-dbcmd.collStats) operations require the member to be in [`PRIMARY`](https://www.mongodb.com/docs/manual/reference/replica-states.md#mongodb-replstate-replstate.PRIMARY) or [`SECONDARY`](https://www.mongodb.com/docs/manual/reference/replica-states.md#mongodb-replstate-replstate.SECONDARY) state. If the member is in another state, such as [`STARTUP2`](https://www.mongodb.com/docs/manual/reference/replica-states.md#mongodb-replstate-replstate.STARTUP2), the operation errors.

## Compatibility

This method is available in deployments hosted in the following environments:

- [MongoDB Atlas](https://www.mongodb.com/docs/atlas): The fully managed service for MongoDB deployments in the cloud

**Note:**

This command is supported in all MongoDB Atlas clusters. For information on Atlas support for all commands, see [Unsupported Commands.](https://www.mongodb.com/docs/atlas/unsupported-commands/)

- [MongoDB Enterprise](https://www.mongodb.com/docs/manual/administration/install-enterprise.md#std-label-install-mdb-enterprise): The subscription-based, self-managed version of MongoDB

- [MongoDB Community](https://www.mongodb.com/docs/manual/administration/install-community.md#std-label-install-mdb-community-edition): The source-available, free-to-use, and self-managed version of MongoDB