QuickBooks uses this percentage to calculate the sales price of items that
have both a cost and a sales price.
You'll see the effect of the default markup percentage when you create
inventory part, inventory assembly, non-inventory part, service, and other charge
items. When you enter the item's cost, QuickBooks calculates the sales
price and enters it in the Sales Price field. For example, entering a cost
of $10.00 when the markup is 25% causes QuickBooks to fill in the sales price
as $12.50. If you don't want to use the default markup for an item, change
the sales price that QuickBooks fills in.
Where to find this preference:
Open the time and expenses preferences.
Go to the Edit menu and click Preferences.
In the Preferences window, click Time & Expenses in the list on the left.
Click the Company Preferences tab.