Your bestseller may not be your best product.
Some products drive turnover but leave almost nothing after discounts, logistics, returns and advertising. Margly finds them automatically.
- Result without an email
- Tax and tax-free modes
- CZK, EUR and USD
- Cost of goods−55.4 %
- Logistics−7.7 %
- Marketing−18.2 %
- Operations−10.4 %
- Left over8.3 %
One product, its whole economics.
Work out one product's contribution after discounts, shipping, returns and advertising. Then run the same logic across the catalogue.
Currency changes only the unit and number format. Your entered values are never converted.
Without the number of units you can't compare turnover with profit.
How much of your ad budget falls on a single unit sold. If you don't know, leave it empty — we won't fill anything in for you.
Enter your numbers on the left.
The result appears as soon as you fill the first field. Nothing is sent anywhere — the maths runs in your browser.
Same order. Completely different picture.
An ordinary calculator stops at the difference between selling and purchase price. Here we go further — to the amount you can actually spend on running and growing the business.
Gross margin
- Achieved price excl. taxCan't be calculated
- Cost of goodsCan't be calculated
- Gross profitCan't be calculated
Contribution after costs
- Gross profitCan't be calculated
- Per unitCan't be calculated
- Left after costsCan't be calculated
Fill in the calculator above and both cards recalculate on your numbers.
How do you tell which products actually make money?
The product with the highest turnover need not be the one that earns you most. What decides it is contribution per unit times units sold. A deep discount, expensive shipping and frequent returns can turn a bestseller into an item that feeds the warehouse but not you.
What does a worked example look like?
You sell at 1,210 including 21% tax, buy at 605, shipping works out at 121, returns at 55 and advertising at 100 per unit. Contribution is 245 per unit; at 250 units sold that's 61,250. Raise the price to 1,331 and sell the same amount and you'd gain 25,000 — but nobody knows in advance how many people won't buy at the higher price.
How does tax enter the calculation?
Before anything is added up, every amount is converted to one economic basis. If you're registered for tax, output tax comes off revenue and input tax comes off costs, because you can reclaim it. The payment fee isn't converted — financial services are exempt, so there's nothing to reclaim. The country preset is only a suggestion; what you set is what counts.
- Achieved price
- list price − average discount
- Contribution per unit
- achieved price − purchase price − shipping − payment fee − returns − advertising
- Total
- contribution per unit × units sold
- Price change
- units × (new contribution − old contribution)
Counting a return twice
The refunded amount reduces revenue. Return shipping and the work involved are an extra cost. Put both in one field and the result looks worse than it is.
Advertising folded into the margin
You can't derive a break-even point from a margin that already has advertising deducted — it's circular and the number means nothing. That's why we start from the contribution before advertising.
Mixing prices with and without tax
Revenue including tax minus a purchase price excluding tax gives you a margin that doesn't exist anywhere. So the calculator converts everything to one basis first.
You might recognise one of these.
A few products drive your revenue and profit still doesn't move.
Work out contribution per unit and across the volume — that's what really ranks products.
You're planning a promotion and don't know how many extra units pay for it.
The price scenario shows what happens to contribution at unchanged volume.
You want to drop slow movers but worry you'll cut something you need.
Compare a product against your own average, not against someone else's benchmark.
You worked out one order. Margly does it for all of them.
You worked out one product. Margly goes through the whole catalogue and ranks it by what each item really brings in.
- 1Pick your platformShoptet, Upgates, Shopify or WooCommerce.
- 2Let it load real dataOrders, products and purchase prices come in on their own.
- 3Fix the biggest impact firstA specific opportunity, an amount and a recommended step.
14 days free · no card required · data in the EU
- Do todayMove budget out of three campaigns below break-even.Sample
- ProductsRaise visibility of a product with above-average margin.Sample
- ShippingA carrier whose shipping balance doesn't add up.Sample
Frequently asked questions
Do I have to sign up to see the result?
What's the difference between margin and markup?
Why might a bestseller not be your best product?
Can the calculator show the impact of a price increase?
More tools
Profit margin calculator
Go from basic margin and markup to profit after fulfilment, fees, returns and advertising. Calculate one order manually — then let Margly run the same logic across your entire store.
Open tool →Break-even ROAS calculator
It depends on your purchase price, shipping, fees, returns and on the value you send to the ad platform. Work out your own break-even point.
Open tool →Net margin calculator
Build a simple income statement from revenue through goods, logistics and marketing all the way to operating and net profit.
Open tool →Let Margly calculate your whole store.
Orders, products, purchase prices, advertising and operating costs in one view. On your data, not on a generic benchmark.
Find profitable and loss-making products14 days free · no card required · data in the EU