Amount Formulas
With Amount Formulas you can substantiate the quantity of a line by splitting it into several parts. Each part is calculated with a formula (e.g. the volume of a tree), and the sum of all parts becomes the quantity of the line. You can show this calculation on the document, so that your customer sees how you arrived at a given quantity — or keep it hidden for internal use.
Besides quotations, this also works on orders, invoices, supply orders and the progress claim. Handy, for example, for an earthworks contractor who wants to record per row from which house number to which house number something was carried out: the name of a row carries just as much information as the numbers.
For example: we draw up a quotation to remove and shred a few trees, with a price per cubic metre. On site we measured the number of trees, with an estimate of the average radius and height. By entering this in detail, we get a correct volume — and we can pass that substantiation on to the customer on the quotation document.
Use
To use an amount calculation on a line:
- Hover with your mouse over the Quantity of a line and click the coloured info icon.
- Choose the formula in the combobox at the top right (e.g. "Volume m3").
- Click Add line.
- Give the new line a clear name and fill in the parameters. The columns correspond to the variables from the formula.
- Check the result; the total at the bottom becomes the quantity of the quotation line.
- Save by clicking away or by clicking the cross.
This window contains two options:
- Show on PDF: activate this to show the amount calculation on the document. Leave it off to keep the substantiation internal only.
- Show separate formula: the formula used is sometimes hard to read or not intended for the customer. Activate this option to show a readable formula (e.g. "Pi x r² x h") on the PDF instead.
As long as there is an amount formula on a line, you can no longer adjust the quantity of that line manually — delete the formula first if you do want to.
Settings
To be able to use Amount Formulas:
- Go to General settings > Master data and switch Amount Formulas on.
- Open Amount Formulas and add a new formula with a name and a formula.
- In the Formula field you enter the calculation, e.g.
lengte * breedte. Every word you use automatically becomes a parameter to fill in (in order of appearance). - Save the settings.
- Use the formula in a supported module such as a quotation, order, invoice, supply order or progress claim.
Tip: if you rename the variable names in a formula later, the values already entered are kept — they are stored by position. Do be careful when adding, deleting or rearranging variables.
Formula possibilities
Formula | Explanation | Example | Result |
|---|---|---|---|
+ | Adds two numbers | 5 + 6 | 11 |
- | Subtracts two numbers | 8 - 3 | 5 |
* | Multiplies two numbers | 9 * 3 | 27 |
/ | Divides two numbers | 9 / 3 | 3 |
% | Modulo: gives the remainder after division | 8 % 3 | 2 |
^ | Exponent | 5 ^ 2 | 25 |
round( x ) | Rounding | round(1.6) | 2 |
ceil( x ) | Rounding up | ceil(2.4) | 3 |
floor( x ) | Rounding down | floor(2.7) | 2 |
min(x,y,z) | Gives the lowest number | min(5,9) | 5 |
max(x,y,z) | Gives the highest number | max(17,5,9) | 17 |
sqrt( x ) | Square root of x | sqrt(64) | 8 |
The formulas use the math.js library; see this list for all possibilities.
Updated on: 04/09/2026
Thank you!