# Convert sensor units

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

Create a calibration action that converts a sensor reading into the required measurement unit.

In some cases, those units may not match your preferred unit of measurement. For example, a water level sensor may transmit data in feet when your team works in metres. You can use the Calibrations feature to apply a mathematical conversion to the raw sensor value, so that Orion Data displays the reading in the correct unit. This article explains how to create a calibration that converts a sensor’s unit of measurement.

## Before you begin

Calibrations are configured at the device level, within the **Calibrations** tab of a specific device. You will need to know:

- Which device contains the sensor you want to convert
- Which sensor channel needs the conversion
- The mathematical formula required to convert the raw unit to your target unit

> **Note:**
>
> This process creates a new calibration from blank. If your organisation uses calibration templates, speak with your administrator before proceeding, as a template may already exist for your conversion.

## Steps

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

![Main menu open with Devices highlighted](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/main-menu-open-devices.png)

1. Select **Devices** from the menu. The **Devices** page will open.
2. Locate the device you wish to configure. 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/converting-sensor-units-using-calibrations/devices-list-button-actions-column-device-row.png)

1. Select the **Calibrations** tab within the device.

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

1. Select the sensor channel you need to apply the unit conversion to.

![Device Calibration tab with the Select Sensor dropdown highlighted, showing the Water Level channel](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/device-calibration-tab-select-sensor-dropdown-water-level-channel.png)

1. Select **Create from blank**. A blank calibration page will open.

![Calibration Step Groups for the Water Level channel with the Create from blank button highlighted](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/calibration-step-groups-water-level-channel-create-from-blank-button.png)

1. Select **Add Action**. A new action row will appear.
2. In the first **Select action** field, select **Sensor value**, then choose the sensor channel you are converting.
3. Set the operator (the symbol between the two action fields) to match the mathematical operation required for your conversion:

![New calibration action set to Sensor value for Water Level, with the operator dropdown on the next line highlighted](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/new-calibration-action-set-sensor-value-water-level-operator-dropdown-next-line.png)

| Conversion type | Operator to select |
| --------------- | ------------------ |
| Addition        | **+**              |
| Subtraction     | **-**              |
| Multiplication  | **x**              |
| Division        | **/**              |

1. In the second **Select action** field, select **Value**, then enter the conversion factor.

> **Example:**
>
> To convert a water level reading from feet to metres, set the first action to **Sensor value** (Water level), the operator to **/**, and the value to **3.28084**.

![Calibration action dividing the Water Level sensor value by the constant 3.281, with the Save button highlighted](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/calibration-action-dividing-water-level-sensor-value-by-constant-3-281-save.png)

1. Select **Save**. A confirmation window will appear.
2. In the confirmation window, select **Close** to apply the calibration to new data going forward. If you also want the conversion applied to your existing historical data, select **Force recalculation** before closing.

![Confirm Calibration window saying the calibration affects only future data and to use Force Recalculation for existing data, with Close highlighted](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/confirm-calibration-window-saying-calibration-affects-only-future-data-use-force.png)![Saved calibration step group named divide value from Water Level to 3.28, with the Force-recalculation button highlighted](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/saved-calibration-step-group-named-divide-value-from-water-level-3-28-force.png)![Green message: Data recalculation has started. Process will take a few minutes to complete.](https://docs.oriondata.io/images/portal/calibrations/converting-sensor-units-using-calibrations/green-message-data-recalculation-has-started-process-will-take-few-minutes.png)

## Summary

This article covered how to create a calibration in Orion Data that converts a sensor’s raw unit of measurement to a preferred unit. You selected a sensor channel, defined a mathematical action using the sensor value and a conversion factor, and saved the calibration. You also had the option to apply the conversion retroactively to existing data using force recalculation.

## Next Steps

- Review other sensors on the same device to identify any additional unit conversions required
- Explore calibration conditions if you need the conversion to apply only under certain circumstances
- Contact your administrator if you require a calibration template to standardise this conversion across multiple devices

## Related articles

- [Calibrations and sensor values](https://docs.oriondata.io/portal/calibrations/understanding-calibrations/)
- Using calibration templates
- [Force recalculating calibration data](https://docs.oriondata.io/portal/calibrations/using-force-recalculation/)
- Setting sensor alarm thresholds