Amount Formulas
With Amount Formulas you can substantiate a line's quantity by splitting it into several parts. Each part is computed with a formula (e.g. the volume of a tree), and the sum of all parts becomes the line's quantity. You can show this calculation on the document, so 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, purchase orders and the progress statement. Handy for example for an earthworks contractor who wants to record per row from which house number to which house number a task was carried out: the name of a row carries as much information as the numbers.
For example: we create a quotation to remove and shred some trees, priced 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 share this substantiation with the client on the quotation document.
Use
To use an amount calculation on a line:
- Hover over the Quantity of a line and click the coloured info icon.
- Choose the formula in the dropdown on the 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 formula's variables.
- Check the result; the total becomes the quotation line's quantity.
- Save by clicking away or clicking the cross.
This window has two options:
- Show on PDF: activate this to show the amount calculation on the document.
- Show separate formula: display a readable formula (e.g. "Pi x r² x h") on the PDF instead of the actual calculation.
Settings
- Go to General settings > Master data and turn on Amount Formulas.
- Add a new formula with a name and a formula.
- In the Formula field: e.g.
length * width. Each word you use automatically becomes a parameter to fill in. - Save and use the formula in a quotation, order, invoice, purchase order or progress statement.
Tip: if you rename the variables later, the values already entered are kept (stored by position).
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: remainder after division | 8 % 3 | 2 |
^ | Exponent | 5 ^ 2 | 25 |
round( x ) | Rounding | round(1.6) | 2 |
ceil( x ) | Round up | ceil(2.4) | 3 |
floor( x ) | Round down | floor(2.7) | 2 |
min(x,y,z) | Takes the lowest number | min(5,9) | 5 |
max(x,y,z) | Takes the highest number | max(17,5,9) | 17 |
sqrt( x ) | Square root of x | sqrt(64) | 8 |
Formulas use the math.js library; see this list for all possibilities.
Updated on: 03/07/2026
Thank you!