# Recalculate historical sensor data

> For the complete documentation index, see [llms.txt](https://docs.oriondata.io/llms.txt)

Start recalculation after changing a calibration so it can be applied to historical readings.

To apply the updated calibration to existing historical data on the device, you must trigger a Force-recalculation. This article explains when to use Force-recalculation and how to run it.

## When to use Force-recalculation

Use Force-recalculation after you have made any of the following changes to a calibration:

- Added a new calibration to a sensor
- Removed an existing calibration from a sensor
- Modified the settings of an existing calibration

Force-recalculation processes all historical data on the device through the updated calibration. This ensures that charts, dashboards, and exports reflect the corrected values across the full data history, not just from the time of the change.

> **Note:**
>
> The recalculation process may take several minutes to complete depending on the volume of data stored on the device.

## Running a Force-recalculation

1. Select the menu icon (three horizontal lines) in the top left-hand corner of the screen.

![Map view with an arrow pointing to the menu icon in the top left corner](https://docs.oriondata.io/images/portal/calibrations/using-force-recalculation/map-view-menu-icon-top-left-corner.png)

1. Select **Devices** from the menu. The **Devices** page will open.
2. Locate the device you wish to update. Select the arrow icon on the far right of that device row to open the device.

![Devices list with the arrow button in the Actions column of a device row circled](https://docs.oriondata.io/images/portal/calibrations/using-force-recalculation/devices-list-button-actions-column-device-row.png)

1. Within the device, select the **Calibrations** tab.

![Device configuration page with the Calibration tab highlighted](https://docs.oriondata.io/images/portal/calibrations/using-force-recalculation/device-configuration-page-calibration-tab.png)

1. Select the Soft Sensor you need to apply the recalculation to.
2. Make your calibration changes if you have not already done so, then select **Save**. You will be returned to the **Calibrations** page.
3. On the **Calibrations** page, locate and select **Force-recalculation**.

![Calibration tab for the 9am to 9am soft sensor with the Force-recalculation button highlighted](https://docs.oriondata.io/images/portal/calibrations/using-force-recalculation/calibration-tab-9am-9am-soft-sensor-force-recalculation-button.png)

A green confirmation banner will appear in the top right corner of the screen with the message: “Data recalculation has started. Process will take a few minutes to complete.”

![Green message: Data recalculation has started. Process will take a few minutes to complete.](https://docs.oriondata.io/images/portal/calibrations/using-force-recalculation/green-message-data-recalculation-has-started-process-will-take-few-minutes.png)

## Summary

Force-recalculation allows you to apply calibration changes retrospectively to all historical data on a device in Orion Data. After saving a calibration update, select **Force-recalculation** to start the process. A confirmation banner will appear once the recalculation has been initiated.

## Next Steps

- Review your sensor data on the relevant dashboard or chart to confirm the recalculated values appear as expected.
- If the recalculation does not complete or the data does not update, contact your system administrator or EWS Monitoring support.
- Explore calibration templates to apply consistent calibration settings across multiple devices.

## Related articles

- [Calibrations and sensor values](https://docs.oriondata.io/portal/calibrations/understanding-calibrations/)
- Setting up a calibration on a sensor
- Working with soft sensors
- Viewing and editing sensor data in the Data Editor