A busy sales day can feel successful right up until the bills arrive. Product cost is only the beginning: payment fees, marketplace charges, packaging, shipping subsidies, returns and ads can change the result. The safest way to plan is to calculate the economics of one typical order and then test what happens when a cost rises.
Start with a complete profit formula
Profit margin is net profit ÷ selling price × 100. Markup is profit ÷ cost × 100. These percentages use different denominators, so they are not interchangeable. State which one you mean whenever you set a pricing target.
Worked example: a seller pricing in INR
Suppose an independent seller lists an item for ₹999. These are illustrative inputs, not fees quoted by any marketplace:
| Per-order item | Example |
|---|---|
| Customer price | ₹999 |
| Product cost | ₹420 |
| Shipping absorbed | ₹100 |
| Marketplace / transaction fees | ₹109 |
| Packaging | ₹20 |
| Estimated net profit | ₹350 |
| Estimated margin | 35.0% |
The calculation is ₹999 − ₹420 − ₹100 − ₹109 − ₹20 = ₹350. If the business also spends ₹70 in advertising to acquire that order, the estimate falls to ₹280 before any other uncounted costs. The important lesson is to list every cost explicitly.
The same method for a global seller
A $40 order with $13 product cost, $5 shipping, $3 transaction fees and $2 packaging leaves $17, or a 42.5% margin, before returns, ads and tax. The currency changes; the arithmetic does not.
Don't forget returns, discounts and taxes
If some orders are returned, track the actual cost of those returns over time. An expected per-order return allowance can be estimated from your own history, but do not invent a universal return rate. Discounts reduce revenue, while some fees still apply after a promotion. Sales tax, VAT and GST treatment varies by jurisdiction and transaction; a generic calculator cannot determine your legal obligations.
Calculate a base case, a higher-shipping case and a promotional case. If a small change turns your margin negative, revisit the price or cost structure before scaling ads.
Make this a monthly habit
- Recheck supplier prices and packaging costs.
- Compare expected marketplace fees with settlement statements.
- Record returns, replacements and ad spend separately.
- Review profit by product, not just total sales.
- Use one currency and consistent tax treatment within each calculation.
Use the Manglo profit calculator to enter your own numbers. Its output is an estimate, not financial or tax advice.
One small next step.
Use Manglo's free toolkit to put the ideas in this guide into practice. No sign-up required.
Open the profit calculator →