Finance

# Use variable price indexes

Keep values such as a diesel index in one place and let formula and adjustment price modules follow them automatically.

Updated 5 October 2026

**Who can do this:** The pricing permission and the Financial platform feature.

A price variable (also called a variable price index) is a named number that your price modules refer to, such as the current diesel price index or a toll surcharge. When the index changes, you update it once and every module that uses it follows. Two module types use price variables: **Formula** modules, which put the value straight into the calculation, and **Variable adjustment** modules, which adjust their price by how far the value is from a base level. A variable can also hold a different value per period, so prices follow the index that applied on the day of the transport.

## Open the price variables

1. Open the side menu (☰, top right).
2. Choose **Prices**.
3. Click **Price variables** at the top of the **Price configuration** list.
4. Search by name, or click a row to see the variable.

The **Price variable** list shows the **Name**, the variable name and the **Made on** and **Updated on** dates.

## Create a price variable

1. Click **\+ Create price variable**.
2. Enter a **Name**, for example "Diesel price index".
3. Enter the **Variable name**, for example `diesel`. Use letters and digits; other characters, such as spaces or a dollar sign, cannot be typed.
4. Enter the current **Value**, for example 1.62.
5. Optional: switch on **Time-bound** to enter values per period (see below).
6. Click **Save**.

In a formula you write the variable name with a dollar sign in front, for example `$diesel`. The name must match exactly, including capitals: `$Diesel` does not find a variable named `diesel`.

## Values per period

Use **Time-bound** when the index changes over time and every transport should be priced with the value of its own date, for example a monthly diesel index.

1. Open the price variable and click the pencil icon, or create a new one.
2. Switch on **Time-bound**. The **Values per period** section appears.
3. Click **\+ Add period**.
4. Choose the first and last day of the period in the calendar.
5. Enter the **Value** for that period.
6. Repeat for each period, or click **Remove** next to a period to delete it.
7. Click **Save**.

A trip is priced with the value of the period that covers its start date, and a transport order with the period that covers its earliest planned stop. Outside every period, the value at the top of the form is used. When periods overlap, the one that starts latest wins. Vehicles and fleet vehicles use today's value.

## Use the variable in a module

* In a **Formula** module, type the variable name with a dollar sign in the **Formula**, for example `{{ route.distance }} / 1000 * $diesel`.
* In a **Variable adjustment** module, choose the price variable and enter the **Base level**, **Per difference of** and **Change per step**. When the index is above or below the base level, the price is adjusted accordingly.

See [Price modules explained](/en/help/price-modules) for all module types.

## Update or remove a price variable

1. Find the variable in the **Price variable** list.
2. Click **Edit** at the end of the row, or click the row and then the pencil icon.
3. Enter the new **Value**, or add a period for a time-bound variable, and click **Save**.
4. To delete a variable, click **Remove** and confirm.

New price calculations use the new value. Invoices that were already created keep their amounts.

Before you remove a variable, check that no formula still uses it. A formula that refers to a missing variable cannot be calculated correctly.

## Related articles

* [Price modules explained](/en/help/price-modules)
* [Set up price configurations](/en/help/pricing)
* [Pricing categories and cost elements](/en/help/pricing-categories)

## Still need help?

Our support team is happy to answer any question about Transportial.

[Contact support](/en/contact)[Report an issue](/en/report-issue)

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Canonical page: https://transportial.com/en/help/variable-price-indexes