Selling on Amazon.sa with FBA, where do referral and fulfilment fees go in a break-even calculation?
Referral and fulfilment fees are charged on every unit sold, so they go into the variable cost together with the product cost and inbound shipping. Anything you pay monthly regardless of sales, such as a seller plan, is a fixed cost. That split leaves a large variable cost and a thin contribution, which is why the numbers deserve care.
Splitting costs when the marketplace fulfils
- Variable cost per unit: what you paid for the product, the referral fee, the fulfilment fee (pick, pack and delivery), and the unit's share of inbound shipping to the warehouse.
- Fixed cost for the month: a monthly seller plan, product photography, inventory tools, and anyone's wage for running the account.
- The judgement call: storage fees. If they scale with how many units sit in the warehouse, the more accurate move is to spread them over the units you expect to sell and add that to variable cost. If they are roughly the same every month, treat them as fixed.
Do not rely on fee percentages quoted in articles; they vary by category, size and weight. Take the actual amounts from the fee preview in your own account for each product and enter them as money.
An illustrative example
These figures are for illustration only; replace them with your product's. Fixed costs of 5,000, a price of 120 and a variable cost of 78, made up of product 45, fees 27 and inbound shipping 6. The Break-even calculator shows a contribution of 42, a contribution margin ratio of 35%, an exact break-even of 119.05 rounded up to 120 units, and revenue of 14,400 at that volume.
What if fees go up by 12?
Fulfilment fees can rise when your packaging changes size or weight tier. Add 12 to the variable cost, making it 90: the contribution falls to 30, the ratio to 25%, and break-even jumps to 166.67, rounded up to 167 units. That is 47 extra units a month from a fee increase worth only a tenth of the price.
This is the nature of marketplace fulfilment: the fixed part is small but the variable cost is large, so a small change in it shakes the contribution. Before you change the box or add an insert, rerun the numbers.
Putting the result to work
- Compare break-even with the product's actual monthly sales. If they are close, you are working for almost nothing.
- If the contribution is thin, try a new price that absorbs the fees with the Selling-price calculator.
- Check the per-unit margin after fees with the Profit margin calculator.
Common questions
Does the calculator know Amazon's fees?
No. It contains no fee table for any marketplace. You enter the amounts shown in your own account.
I sell several products at different prices. Can I combine them?
The calculator assumes one product. Run each main product separately with its share of fixed costs.
Is VAT included?
No. The tool does not handle tax, so enter prices and costs on whichever basis your books use, and be consistent.