# Memory Usage
# Monitor Collection Memory Usage

*Available as of v1.18.0*

Qdrant lets you inspect a collection's disk space, RAM, and OS page cache usage, summed up across the whole cluster and broken down by component. Use this to plan capacity, diagnose memory pressure, or understand which parts of a collection are resident in memory.

This information is available in the [Qdrant Web UI](/documentation/web-ui/index.md) and through the API.

## Web UI

Open the collection detail page and select the **Memory** tab. It shows the memory breakdown for the collection, updated on demand.

<figure>
  <img width="75%" src="/docs/memory-usage.png">
  <figcaption>
    The Memory tab shows the breakdown of disk, RAM, and cached usage for each component of the collection.
  </figcaption>
</figure>

## Understanding the Fields

The breakdown covers these components:

| Component | Description |
| --- | --- |
| **Total** | Aggregate across all components. |
| **Vectors** | Per dense and multi-dense vector: storage, index, and optionally quantization. |
| **Sparse Vectors** | Per sparse vector: storage and index. |
| **Payload** | Payload storage. |
| **Payload Index** | Per payload field index. |
| **ID Tracker** | Maps external point IDs to internal ones. |

Each component reports four values:

| Field | Description |
| --- | --- |
| **Disk** | Total file sizes on disk. |
| **RAM** | Non-evictable heap RAM: in-memory data structures not backed by memory-mapped files. |
| **Cached** | Evictable RAM: file pages currently resident in the OS page cache. |
| **Expected Cache** | The amount of data that should ideally be cached for best performance. Compare this against **Cached** to see how much of the working set is warm. |

## API

You can retrieve the same data though Qdrant's API:

```bash
curl http://localhost:6333/collections/{collection_name}/memory
```

<!--
The response contains a `result` object with `total`, `vectors`, `sparse_vectors`, `payload`, `payload_index`, and `other` fields. Each field uses the same four-value structure: `disk_bytes`, `ram_bytes`, `cached_bytes`, and `expected_cache_bytes`.

See the [API reference](https://api.qdrant.tech/api-reference) for the full response schema.
-->

## Accuracy

The reported values are estimates. RAM usage is typically underestimated by 10–15% because memory allocated by third-party libraries and the allocator itself isn't accounted for.

On non-Unix systems, **Cached** is always reported as `0`.