Costs directly related to the sale
COGS, shipping/fulfillment and payment fees directly affect the contribution of each order. If one is missing, products or channels can appear more profitable than they are. Fees deserve particular attention when they vary by payment method or provider.
Advertising and returns
Ad spend should be subtracted as a real cost of the period. Refunds and returns reduce the actual value of sales at the same time. Looking only at ad-platform dashboards or only at the store’s gross sales total often leaves those pieces disconnected.
Fixed and other operating costs
Tools, subscriptions, warehousing and other fixed expenses can be added when you want broader business profitability. Keeping direct variable costs separate from fixed costs helps you understand both the economics of sales and the overall financial result.
What to check in practice
FAQ
Which e-commerce expenses are commonly missed?
Payment fees, shipping/fulfillment, returns, discounts and advertising costs often live in separate systems and may never be viewed together.
Do I need every fixed expense before I start?
No. You can start progressively with the most important variable costs and add fixed costs when you want a broader profitability picture.