> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hologram.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Set data usage limits

> Data usage limits help you manage your SIMs' data usage and prevent unexpected charges or overage.

A **data usage limit** defines the total amount of data the device can consume during a billing period. When a SIM reaches the limit you set, its data usage is paused. The organization's owner will also get an email notifying them of the pause. Data usage limits are checked at the close of each data session.

If the SIM's data plan has included data, the data limit has a minimum value of that included data. This value is the `overagelimit` parameter returned in the REST API, and is checked above plan included data amounts.

## How to set a limit for a single SIM

1. Open a SIM from the SIMs pages or using global search.
2. Click the **Manage SIM** menu in the header and choose **Set data usage limits**.
3. Enter your settings:
   * **Overage limit**: Cap in bytes/KB/MB/GB (SIM pauses when reached)
   * **Threshold alert**: Optional warning level (does not pause)
   * **SMS limit**: Optional cap on SMS usage
4. Confirm the update.

## How to set usage limits in bulk

1. Navigate to the **SIMs** section in your dashboard.
2. Select up to 10 SIMs in the SIMs table.
3. Open the **Manage SIMs** menu and choose **Set data usage limits**.
4. Configure the same settings (overage limit, threshold alert, SMS limit).
5. Review and apply the changes.

## How to set usage limits using the REST API

<Card title="Update data limits (bulk)" href="/api/1/devices/batch/usagelimit/post" horizontal>
  Update SIM data usage limits in bulk <code>POST /devices/batch/usagelimit</code>
</Card>

<Note>
  **Note:** Set `overagelimit` in bytes; use `-1` for unlimited. Optional fields include `datathreshold` (alert only) and `smslimit`.
</Note>

## Subscribing to data usage limit events

SIMs that reach a data usage limit will create an event in the **Event monitoring** section of your dashboard.

You can subscribe to these events to receive email or webhook notifications when a SIM's data usage limit is reached using [Alerts](/guides/cloud-and-tools/event-monitoring-and-alerts-overview).

## Why did my SIM pause before or after my exact limit?

Data usage limits are checked at the **close of each data session**, not continuously during a session. Your SIM reports its usage when a session ends, and Hologram pauses the SIM if that total has reached or exceeded your limit.

Because of this, the pause happens at a session boundary rather than at the exact byte:

* If a session pushes cumulative usage past your limit, the SIM pauses when that session closes — so a SIM can use somewhat *more* than the limit within a single long session before pausing.
* A SIM can also appear to pause slightly *below* a round number, because the limit was reached partway through a session and enforced at the next session close.

When a limit pauses a SIM, it moves to the **Paused by system** status. To resume it, raise or remove the limit — usage restarts automatically. See [what causes the "Paused by system" status](/guides/troubleshooting/paused-by-system-sim-status).

In addition, **data usage limits are checked against the SIM's 30-day billing period** that began on the day it was activated (making it an Active SIM). If you have monthly invoicing, this may not align with monthly billing periods for your organization, leading to data limit enforcement behavior that doesn't exactly match what you see in your dashboard.

## Related actions

<Card title="Set data warning thresholds" href="/dashboard/sim-actions/set-data-warning-threshold">
  Set a data warning threshold for your SIMs to receive notifications when a certain amount of data is reached.
</Card>

<Card title="Pause or resume SIMs" href="/dashboard/sim-actions/pause-resume-sims">
  Pause or resume SIMs to prevent or allow data usage.
</Card>

<Card title="Change data plans" href="/dashboard/sim-actions/change-data-plans">
  Change data plans for your SIMs.
</Card>