Calculation Methods for Expense Costs

Overview

Every Expense Cost can be calculated in one of three ways. Choosing the right method ensures your profit estimates match how each cost actually behaves in the real world.

Method 1: Fixed Amount

Enter a flat dollar value. This is best for costs that don't change regardless of the sale price.

Example: COGS = $4.50

Method 2: Percentage of a Reference Column

Enter a percentage applied to a reference column (such as Total Item Price). Best for fees that scale with the sale amount.

Example: a custom Listing Royalty cost = 6.5% of Total Item Price

Method 3: Fixed Amount + Percentage of a Reference Column

A combination of a flat fee plus a percentage. Used when a cost has both a base component and a variable component.

Example: Payment processing = $0.30 + 2.9% of Total Item Price

How to Set Calculation Method

You choose the calculation method when you create or edit an Expense Cost - the cost form has a Calculation Method selector (Fixed Amount, Percentage of a Reference Column, or Fixed Amount + Percentage of a Reference Column), and for the percentage methods you also pick the reference column it's based on. See "Creating and Managing Custom Expense Groups & Costs" for the full walkthrough.

The Modify Expense & Profit modal (click the kebab menu on any row) doesn't change the method - it lets you adjust a cost's value for that specific variant and click Calculate to simulate the projected profit and margin before saving.