Overview
A parameter is a named value saved on your estimate, such as Initial Site Clean: 300 m². Each parameter has a name, a quantity and a unit of measurement, and JACK gives it a token based on its name, for example {initial_site_clean}.
Parameters live on the Parameters tab of each estimate and estimate template. You can use a parameter in two ways:
Link it to costing items and assemblies from the Parameters tab, so their quantity matches the parameter.
Add it to a formula in the Quantity Calculator, for example {initial_site_clean} * 1.1 to allow 10% extra.
💡 When you change a parameter’s quantity, every item linked to it recalculates.
Creating a Parameter
Navigate to Estimates and select your estimate.
Click the Parameters tab.
Click + New Parameter.
Enter a name, such as Initial Site Clean. The token appears below as you type.
Enter the quantity in the Qty field.
Select a unit from the UOM dropdown.
Click Create Parameter when you are done.
ℹ️ Each parameter name must be unique on the estimate, and it can’t match the name of an existing takeoff.
💡 Need a unit that isn’t in the list? Select + New UOM at the top of the UOM dropdown. New units are saved to Settings > Data Setup > Units of Measurement, so you can use them across all your estimates.
Renaming a Parameter
On the Parameters tab, click the pencil icon next to the parameter’s name.
Enter the new name.
Click Save.
The token updates to match the new name. Items already linked to the parameter keep working, and their quantities stay the same.
Linking a Parameter to Costing Items and Assemblies
Linking lets one parameter drive the quantity of many items at once, without opening each item.
On the Parameters tab, find the parameter.
Click Link items in the Linked Items & Assemblies column.
In the window that opens, tick the items and assemblies you want to link. Tick a category’s checkbox to select everything in that category.
Check the messages at the bottom of the window that will inform you that existing QTYs will be replaced by the parameter.
Click Link Items.
⚠️ If you tick an item that already has its own calculation, linking replaces it. The message at the bottom of the window shows how many calculations will be replaced before you click Link Items.
The linked items now appear in the Linked Items & Assemblies column, grouped by cost category. Their quantities now come from the parameter.
ℹ️ Assemblies: Linking an assembly sets the assembly’s own quantity. It doesn’t change the quantities of the items inside it.
Unlinking Items
To unlink a single item from the Parameters tab, click the × on its chip in the Linked Items & Assemblies column.
To unlink several items at once, open the link window again, untick them, and click Link Items.
You can also unlink an item from the Costings tab. Click the item’s Qty, then click Unlink. JACK asks you to confirm, because this also removes the item from the parameter’s linked list.
However you unlink an item, it keeps its current quantity, and that quantity no longer updates when the parameter changes.
Using Parameters in the Quantity Calculator
Use the calculator when an item’s quantity needs more than the parameter alone, such as a wastage allowance or a multiplier.
Navigate to your estimate and click the Costings tab.
Click the Qty on the costing item.
Click the calculator icon. The Quantity Calculator opens on the right.
Click the Parameters dropdown.
Select the parameter. It’s added to the formula where your cursor is.
Add any operators or numbers, for example {flooring} * 1.1
Click Save.
To create a parameter without leaving the calculator, select + New Parameter at the top of the Parameters dropdown. Your formula stays in place, and the new parameter is added to it once it’s saved.
ℹ️ Any item whose formula includes a parameter also appears in that parameter’s Linked Items & Assemblies list on the Parameters tab.
Deleting a Parameter
You can only delete a parameter when no items are linked to it. While it’s in use, the trash icon is greyed out and shows how many calculations use it.
Unlink any items using the parameter.
Click the trash icon on the parameter’s row.
Confirm the deletion.