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# Price revision formulas on the progress claim

Does your contract contain a **revision clause**? Then you may adjust the accepted prices because wages and materials have become more expensive since the tender. In Robaws you do that with a **revision formula** on the [progress claim](https://support.robaws.com/en/article/progress-claims-general-explanation-1ja6eom/).

A revision formula produces a coefficient. Robaws multiplies the unit price of every progress claim line concerned by that coefficient: **revised unit price = unit price × value of the formula**. The difference between the two is the price revision that you charge.

|| You fill in the formula and its parameters yourself, exactly as they appear in your contract. Robaws does not retrieve any index figures — you enter the values of the parameters yourself, per progress claim.

## The list of revision formulas

You manage the formulas centrally. Go to the overview of the progress claims and click the **'Process claim formulas' action button** at the top. Click **'+'** to add a formula, or open an existing formula to change it.

A formula consists of:

| Field | What it is for |
| ---- |
| **Name** | The description of the formula, for example 'Revision wages and materials'. |
| **Shorthand** | The code that you choose in the 'Formula' column in the progress claim. Keep it short. |
| **Formula** | The calculation itself, built up with the parameters that you define below it. |
| **Description** | Free explanation, for example the reference to the contract article. |
| **Value** | The result of the formula: the coefficient by which the unit prices are multiplied. |

Next to the formula is the **Parameters** card. That is where you put the separate components of your formula (for example the index at the time of tender and the index of the month of execution).

## Applying a revision in the progress claim

1. Assign a formula per progress claim line in the **Formula** column.
2. After the first assignment, the message **Formula changed** appears briefly, with the link **Apply for all lines**. Click it to set the same formula on all lines in one go.
3. Do you only want some of the lines? Select those lines with the checkboxes and right-click. Choose **Edit**, choose the **Formula** field in the window that opens, select the correct formula and click **Edit** to set it on all selected lines in one go.

Under the **Formulas** tab you see which formulas are used in this progress claim. An empty tab means that no revision has been applied. The right-hand column lists all parameters of every formula. You adjust those parameters here **per progress claim**, so that the price of the lines concerned changes along with them without you touching the central formula.

![Revision formula in the progress claim](https://storage.crisp.chat/users/helpdesk/website/-/e/a/d/f/eadf6dec760ec000/image_nh1x3x.png =800x234)

|| Rounding happens **per line**, not on the total. That can give a difference of a few cents compared with a calculation on the total amount.

## PDF of the price revision

In the progress claim you request the **Pricerevision** document via the **'Pdf' action button**. That document contains:

* the general data of the progress claim;
* a table per formula with the columns **Revision Formula**, **To revise**, **Pricerevision** and **Amount revision incl.** — the lines without a formula are grouped together on the 'None' row;
* per formula used, the calculation itself, its value and the parameters filled in.

## Invoicing

On the invoice, the price revision always appears as a **separate line** next to the normal progress claim lines, so that the distinction stays clear. You set the text of that line via **settings > progress claims** in the **Revision invoice linetext** field; see the [settings of the progress claims](https://support.robaws.com/en/article/progress-claims-settings-15uxwd9/).